AIX 6.1 SECURITY TECHNICAL IMPLEMENTATION GUIDE

506procedures

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Severity
CurrentPublished Fri Oct 26 2018
Objective ID
Severity
Discussion
V-1010
medium
World-writable files and directories make it easy for a malicious user to place potentially compromising files on the system.

The only authorized public directories are those temporary directories supplied with the system or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system and by users for temporary file storage (e.g., /tmp) and for directories requiring global read/write access.
V-1011
low
Inetd or xinetd logging and tracing allows the system administrators to observe the IP addresses that are connecting to their machines and to observe what network services are being sought. This provides valuable information when trying to find the source of malicious users and potential malicious users.
V-1013
high
The ability to boot from removable media is the same as being able to boot into single user, or maintenance, mode without a password. This ability could allow a malicious user to boot the system and perform changes that could compromise or damage the system. It could also allow the system to be used for malicious purposes by a malicious anonymous user.
V-1023
medium
Internet Network News (INN) servers access Usenet newsfeeds and store newsgroup articles. INN servers use the Network News Transfer Protocol (NNTP) to transfer information from the Usenet to the server and from the server to authorized remote hosts.

If this function is necessary to support a valid mission requirement, its use must be authorized and approved in the system accreditation package.
V-1026
medium
SWAT is a tool used to configure Samba. As it modifies Samba configuration, which can impact system security, it must be protected from unauthorized access. SWAT authentication may involve the root password, which must be protected by encryption when traversing the network.

Restricting access to the local host allows for the use of SSH TCP forwarding, if configured, or administration by a web browser on the local system.
V-1027
medium
The /usr/lib/smb.conf file allows access to other machines on the network and grants permissions to certain users. If it is owned by another user, the file may be maliciously modified and the Samba configuration could be compromised.
V-1028
medium
If the smb.conf file has excessive permissions, the file may be maliciously modified and the Samba configuration could be compromised.
V-1029
medium
If the smbpasswd file is not owned by root, the smbpasswd file may be maliciously accessed or modified, potentially resulting in the compromise of Samba accounts.
V-1030
medium
Samba increases the attack surface of the system and must be restricted to communicate only with systems requiring access.
V-1032
medium
The ability to change passwords frequently facilitates users reusing the same password. This can result in users effectively never changing their passwords. This would be accomplished by users changing their passwords when required and then immediately changing it to the original value.
V-1046
high
If a user accesses the root account (or any account) using an unencrypted connection, the password is passed over the network in clear text form and is subject to interception and misuse. This is true even if recommended procedures are followed by logging on to a named account and using the su command to access root.
V-1047
medium
Even though communications are encrypted, an additional layer of security may be gained by extending the policy of not logging directly on as root. In addition, logging in with a user-specific account preserves the audit trail.
V-1048
medium
Audio and video devices that are globally accessible have proven to be another security hazard. There is software that can activate system microphones and video devices connected to user workstations and/or X terminals. Once the microphone has been activated, it is possible to eavesdrop on otherwise private conversations without the victim being aware of it. This action effectively changes the user's microphone to a bugging device.
V-1049
medium
Audio and video devices that are globally accessible have proven to be another security hazard. There is software that can activate system microphones and video devices connected to user workstations and/or X terminals. Once the microphone has been activated, it is possible to eavesdrop on otherwise private conversations without the victim being aware of it. This action effectively changes the user's microphone to a bugging device.
V-1056
medium
If the group-owner of the smb.conf file is not root or a system group, the file may be maliciously modified and the Samba configuration could be compromised.
V-1058
medium
If the smbpasswd file is not group-owned by root, the smbpasswd file may be maliciously accessed or modified, potentially resulting in the compromise of Samba accounts.
V-1059
medium
If the smbpasswd file has a mode more permissive than 0600, the smbpasswd file may be maliciously accessed or modified, potentially resulting in the compromise of Samba accounts.
V-1061
medium
Without privileged group owners, audio devices will be vulnerable to being used as eaves-dropping devices by malicious users or intruders to possibly listen to conversations containing sensitive information.
V-11940
high
An operating system release is considered "supported" if the vendor continues to provide security patches for the product. With an unsupported release, it will not be possible to resolve security issues discovered in the system software.
V-11941
medium
A file integrity baseline is a collection of file metadata which is to evaluate the integrity of the system. A minimal baseline must contain metadata for all device files, setuid files, setgid files, system libraries, system binaries, and system configuration files. The minimal metadata must consist of the mode, owner, group owner, and modification times. For regular files, metadata must also include file size and a cryptographic hash of the file’s contents.
V-11945
medium
Changes in system libraries and binaries can indicate compromise or significant system events, such as patching needing to be checked by automated processes and the results reviewed by the SA.

NOTE: The frequency may be increased to daily, if necessary, in accordance with the contingency plan.
V-11946
medium
Reserved UIDs are typically used by system software packages. If non-system accounts have UIDs in this range, they may conflict with system software, possibly leading to the user having permissions to modify system files.
V-11947
medium
The use of longer passwords reduces the ability of attackers to successfully obtain valid passwords using guessing or exhaustive search techniques by increasing the password search space.
V-11973
medium
To enforce the use of complex passwords, minimum numbers of characters of different classes are mandated. The use of complex passwords reduces the ability of attackers to successfully obtain valid passwords using guessing or exhaustive search techniques. Complexity requirements increase the password search space by requiring users to construct passwords from a larger character set than they may otherwise use.
V-11975
medium
To enforce the use of complex passwords, the number of consecutive repeating characters is limited. Passwords with excessive repeated characters may be more vulnerable to password-guessing attacks.
V-11976
medium
Limiting the lifespan of authenticators limits the period of time an unauthorized user has access to the system while using compromised credentials and reduces the period of time available for password-guessing attacks to run against a single password.
V-11977
medium
Limiting the lifespan of authenticators limits the period of time an unauthorized user has access to the system while using compromised credentials and reduces the period of time available for password-guessing attacks to run against a single password. Locking the password for non-interactive and automated processing accounts is preferred as it removes the possibility of accessing the account by a password. On some systems, locking the passwords of these accounts may prevent the account from functioning properly. Passwords for non-interactive/automated processing accounts must not be used for direct logon to the system.
V-11979
medium
Direct login with the root account prevents individual user accountability. Acceptable non-routine uses of the root account for direct login are limited to emergency maintenance, the use of single-user mode for maintenance, and situations where individual administrator accounts are not available.
V-11980
medium
If successful and unsuccessful logins and logouts are not monitored or recorded, access attempts cannot be tracked. Without this logging, it may be impossible to track unauthorized access to the system.
V-11981
medium
Global initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon.
V-11982
medium
Global initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.
V-11983
medium
Global initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.
V-11984
medium
If the skeleton files are not protected, unauthorized personnel could change user startup parameters and possibly jeopardize user files. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.
V-11985
medium
The executable search path (typically the PATH environment variable) contains a list of directories for the shell to search to find executables. If this path includes the current working directory or other relative paths, executables in these directories may be executed instead of system commands. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, two consecutive colons, or a single period, this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths.
V-11986
medium
The executable search path (typically the PATH environment variable) contains a list of directories for the shell to search to find executables. If this path includes the current working directory or other relative paths, executables in these directories may be executed instead of system commands. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, two consecutive colons, or a single period, this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths.
V-11987
medium
A plus (+) in system accounts files causes the system to lookup the specified entry using NIS or LDAP. If the system is not using NIS or LDAP, no such entries should exist.
V-11988
high
The .rhosts, .shosts, hosts.equiv, and shosts.equiv files are used to configure host-based authentication for individual users or the system. Host-based authentication is not sufficient for preventing unauthorized access to the system.
V-11989
medium
The .rhosts files are used to specify a list of hosts permitted remote access to a particular account without authenticating. The use of such a mechanism defeats strong identification and authentication requirements.
V-11990
medium
If a public directory has the sticky bit set and is not group-owned by a system GID, unauthorized users may be able to modify files created by others.

The only authorized public directories are those temporary directories supplied with the system or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system and by users for temporary file storage (e.g., /tmp) and for directories requiring global read/write access.
V-11994
medium
To protect the integrity of scheduled system jobs and prevent malicious modification to these jobs, crontab files must be secured.
V-11995
medium
To centralize the management of privileged account crontabs, of the default system accounts, only root may have a crontab.
V-11996
low
Process core dumps contain the memory in use by the process when it crashed. Process core dump files can be of significant size and their use can result in file systems filling to capacity, which may result in Denial of Service. Process core dumps can be useful for software debugging.
V-11997
low
Kernel core dumps may contain the full contents of system memory at the time of the crash. As the system memory may contain sensitive information, it must be protected accordingly. If the kernel core dump data directory is not owned by root, the core dumps contained in the directory may be subject to unauthorized access.
V-11999
medium
A common type of exploit is the stack buffer overflow. An application receives, from an attacker, more data than it is prepared for and stores this information on its stack, writing beyond the space reserved for it. This can be designed to cause execution of the data written on the stack. One mechanism to mitigate this vulnerability is for the system to not allow the execution of instructions in sections of memory identified as part of the stack.
V-12002
medium
Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when IPv4 forwarding is enabled and the system is functioning as a router.
V-12003
low
The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing.
V-12004
medium
Monitoring and recording successful and unsuccessful logins assists in tracking unauthorized access to the system.
V-12005
medium
Unnecessary services should be disabled to decrease the attack surface of the system.
V-12006
medium
The HELP command should be disabled to mask version information. The version of the SMTP service software could be used by attackers to target vulnerabilities present in specific software versions.
V-12010
medium
FTP is typically unencrypted and, therefore, presents confidentiality and integrity risks. FTP may be protected by encryption in certain cases, such as when used in a Kerberos environment. SFTP and FTPS are encrypted alternatives to FTP.
V-12011
medium
The umask controls the default access mode assigned to newly created files. An umask of 077 limits new files to mode 700 or less permissive. Although umask is stored as a 4-digit number, the first digit representing special access modes is typically ignored or required to be zero (0).
V-12014
medium
.Xauthority files ensure the user is authorized to access the specific X Windows host. Excessive permissions may permit unauthorized modification of these files, which could lead to Denial of Service to authorized access or allow unauthorized access to be obtained.
V-12016
medium
If access to the X server is not restricted, a user's X session may be compromised.
V-12017
medium
If unauthorized clients are permitted access to the X server, a user's X session may be compromised.
V-12018
medium
If unauthorized clients are permitted access to the X server, the user's X session may be compromised.
V-12019
medium
The snmpd.conf file contains authenticators and must be protected from unauthorized access and modification. If the file is not owned by root, it may be subject to access and modification from unauthorized users.
V-12020
medium
Syslog messages are typically unencrypted and may contain sensitive information and are, therefore, restricted to the enclave.
V-12021
medium
Unintentionally running a syslog server that accepts remote messages puts the system at increased risk. Malicious syslog messages sent to the server could exploit vulnerabilities in the server software itself, could introduce misleading information in to the system's logs, or could fill the system's storage leading to a Denial of Service.
V-12022
medium
The SSH daemon must be configured for IP filtering to provide a layered defense against connection attempts from unauthorized addresses.
V-12023
medium
If the system is configured for IP forwarding and is not a designated router, it could be used to bypass network security by providing a path for communication not filtered by network devices.
V-12024
medium
Public Instant Messaging (IM) systems are not approved for use and may result in the unauthorized distribution of information. IM clients provide a way for a user to send a message to one or more other users in real time. Additional capabilities may include file transfer and support for distributed game playing. Communication between clients and associated directory services are managed through messaging servers. Commercial IM clients include AOL Instant Messenger (AIM), MSN Messenger, and Yahoo! Messenger.

IM clients present a security issue when the clients route messages through public servers. The obvious implication is potentially sensitive information could be intercepted or altered in the course of transmission. This same issue is associated with the use of public email servers. In order to reduce the potential for disclosure of sensitive Government information and to ensure the validity of official government information, IM clients connecting to public IM services will not be installed. Clients used to access internal or DoD-controlled IM services are permitted.
V-12025
medium
Peer-to-peer file-sharing software can result in the unintentional exfiltration of information. There are also many legal issues associated with these types of utilities including copyright infringement or other intellectual property issues. The ASD Memo "Use of Peer-to-Peer (P2P) File-Sharing Applications across the DoD" states the following:

"P2P file-sharing applications are authorized for use on DoD networks with approval by the appropriate Designated Approval Authority (DAA). Documented requirements, security architecture, configuration management process, and a training program for users are all requirements within the approval process. The unauthorized use of application or services, including P2P applications, is prohibited, and such applications or services must be eliminated."

P2P applications include, but are not limited to, the following:

-Napster,
-Kazaa,
-ARES,
-Limewire,
-IRC Chat Relay, and
-BitTorrent.
V-12026
medium
The use of hard-to-guess NIS domain names provides additional protection from unauthorized access to the NIS directory information.
V-12028
medium
Timely notifications of potential security compromises minimize the potential damage.

Minimally, the system must log these events and the SA and the IAO will receive the notifications during the daily system log review. If feasible, active alerting (such as email or paging) should be employed consistent with the site’s established operations management systems and procedures.
V-12030
medium
If the system's access control program is not configured with appropriate rules for allowing and denying access to system network resources, services may be accessible to unauthorized hosts.
V-12035
high
The SYSTEM attribute in /etc/security/user defines the mechanisms used to authenticate specific user accounts. If the value is set to NONE, other attributes will be used to determine the authentication mechanisms, but if these attributes are not present, no authentication will be performed. To ensure authentication is always used for the system's accounts, the SYSTEM attribute must always be set to a valid setting other than NONE.

V-12049
medium
Network analysis tools allow for the capture of network traffic visible to the system.
V-12765
medium
Virus scanning software can be used to protect a system from penetration by computer viruses and to limit their spread through intermediate systems.
V-22290
medium
A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. Internal system clocks tend to drift and require periodic resynchronization to ensure their accuracy. Software, such as ntpd, can be used to continuously synchronize the system clock with authoritative sources. Alternatively, the system may be synchronized periodically, with a maximum of one day between synchronizations.

If the system is completely isolated (no connections to networks or other systems), time synchronization is not required as no correlation of events or operation of time-dependent protocols between systems will be necessary. If the system is completely isolated, this requirement is not applicable.
V-22291
medium
A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. For redundancy, two time sources are required so synchronization continues to function if one source fails.

If the system is completely isolated (no connections to networks or other systems), time synchronization is not required as no correlation of events or operation of time-dependent protocols between systems will be necessary. If the system is completely isolated, this requirement is not applicable.

NOTE: For the Network Time Protocol (NTP), the requirement is two servers, but it is recommended to configure at least four distinct time servers which allow NTP to effectively exclude a time source not consistent with the others. The system's local clock must be excluded from the count of time sources.
V-22292
low
A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. The network architecture should provide multiple time servers within an enclave providing local service to the enclave and synchronize with time sources outside of the enclave.

If this server is an enclave time server, this requirement is not applicable.

If the system is completely isolated (no connections to networks or other systems), time synchronization is not required as no correlation of events or operation of time-dependent protocols between systems will be necessary. If the system is completely isolated, this requirement is not applicable.
V-22294
medium
A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. If an illicit time source is used for synchronization, the integrity of system logs and the security of the system could be compromised. If the configuration files controlling time synchronization are not owned by a system account, unauthorized modifications could result in the failure of time synchronization.
V-22295
medium
A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. If an illicit time source is used for synchronization, the integrity of system logs and the security of the system could be compromised. If the configuration files controlling time synchronization are not owned by a system group, unauthorized modifications could result in the failure of time synchronization.
V-22296
medium
A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. If an illicit time source is used for synchronization, the integrity of system logs and the security of the system could be compromised. If the configuration files controlling time synchronization are not protected, unauthorized modifications could result in the failure of time synchronization.
V-22297
medium
A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. If an illicit time source is used for synchronization, the integrity of system logs and the security of the system could be compromised. If the configuration files controlling time synchronization are not protected, unauthorized modifications could result in the failure of time synchronization.
V-22298
low
Limiting simultaneous user logins can insulate the system from Denial of Service problems caused by excessive logins. Automated login processes operating improperly or maliciously may result in an exceptional number of simultaneous login sessions.

If the defined value of 10 logins does not meet operational requirements, the site may define the permitted number of simultaneous login sessions based on operational requirements.

This limit is for the number of simultaneous login sessions for EACH user account. This is NOT a limit on the total number of simultaneous login sessions on the system.
V-22299
low
Providing users with feedback on when account accesses last occurred facilitates user recognition and reporting of unauthorized account use.
V-22301
low
To protect the on-screen content of a session, it must be replaced with a publicly-viewable pattern upon session lock. Examples of publicly viewable patterns include screen saver patterns, photographic images, solid colors, or a blank screen, so long as none of those patterns convey sensitive information.

This requirement applies to graphical desktop environments provided by the system to locally attached displays and input devices, as well as, to graphical desktop environments provided to remote systems using remote access protocols.
V-22302
medium
Some common password hashing schemes only process the first eight characters of a user's password, which reduces the effective strength of the password.
V-22303
medium
Systems must employ cryptographic hashes for passwords using the SHA-2 family of algorithms or FIPS 140-2 approved successors. The use of unapproved algorithms may result in weak password hashes that are more vulnerable to compromise.
V-22304
medium
Systems must employ cryptographic hashes for passwords using the SHA-2 family of algorithms or FIPS 140-2 approved successors. The use of unapproved algorithms may result in weak password hashes that are more vulnerable to compromise.
V-22306
medium
To ensure password changes are effective in their goals, the system must ensure old and new passwords have significant differences. Without significant changes, new passwords may be easily guessed based on the value of a previously compromised password.
V-22307
medium
An easily guessable password provides an open door to any external or internal malicious intruder. Many computer compromises occur as the result of account name and password guessing. This is generally done by someone with an automated script using repeated logon attempts until the correct account and password pair is guessed. Utilities, such as cracklib, can be used to validate that passwords are not dictionary words and meet other criteria during password changes.
V-22308
low
Configuring a supplemental group for users permitted to switch to the root user prevents unauthorized users from accessing the root account, even with knowledge of the root credentials.
V-22309
medium
File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files.
V-22310
medium
The library search path environment variable(s) contains a list of directories for the dynamic linker to search to find libraries. If this path includes the current working directory or other relative paths, libraries in these directories may be loaded instead of system libraries. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon or two consecutive colons, this is interpreted as the current working directory. Entries starting with a slash (/) are absolute paths.
V-22311
medium
The library preload list environment variable contains a list of libraries for the dynamic linker to load before loading the libraries required by the binary. If this list contains paths to libraries relative to the current working directory, unintended libraries may be preloaded. This variable is formatted as a space-separated list of libraries. Paths starting with (/) are absolute paths.
V-22312
medium
Files without a valid group owner may be unintentionally inherited if a group is assigned the same GID as the GID of the files without a valid group owner.
V-22313
medium
Restricting permission on daemons will protect them from unauthorized modification and possible system compromise.
V-22314
medium
Restricting permissions will protect system command files from unauthorized modification. System command files include files present in directories used by the operating system for storing default system executables and files present in directories included in the system's default executable search paths.
V-22315
medium
If the system log files are not protected, unauthorized users could change the logged data, eliminating its forensic value. Authorized software may be given log file access through the use of extended ACLs when needed and configured to provide the least privileges required.
V-22316
low
If manual pages are compromised, misleading information could be inserted, causing actions that may compromise the system.
V-22317
medium
Unauthorized access could destroy the integrity of the library files.
V-22318
medium
NIS/NIS+/yp files are part of the system's identification and authentication processes and are, therefore, critical to system security. ACLs on these files could result in unauthorized modification, which could compromise these processes and the system.
V-22319
medium
The resolv.conf (or equivalent) file configures the system's DNS resolver. DNS is used to resolve host names to IP addresses. If DNS configuration is modified maliciously, host name resolution may fail or return incorrect information. DNS may be used by a variety of system security functions, such as time synchronization, centralized authentication, and remote system logging.
V-22320
medium
The resolv.conf (or equivalent) file configures the system's DNS resolver. DNS is used to resolve host names to IP addresses. If DNS configuration is modified maliciously, host name resolution may fail or return incorrect information. DNS may be used by a variety of system security functions, such as time synchronization, centralized authentication, and remote system logging.
V-22321
medium
The resolv.conf (or equivalent) file configures the system's DNS resolver. DNS is used to resolve host names to IP addresses. If DNS configuration is modified maliciously, host name resolution may fail or return incorrect information. DNS may be used by a variety of system security functions, such as time synchronization, centralized authentication, and remote system logging.
V-22322
medium
The resolv.conf (or equivalent) file configures the system's DNS resolver. DNS is used to resolve host names to IP addresses. If DNS configuration is modified maliciously, host name resolution may fail or return incorrect information. DNS may be used by a variety of system security functions such as time synchronization, centralized authentication, and remote system logging.
V-22323
medium
The /etc/hosts file (or equivalent) configures local host name to IP address mappings that typically take precedence over DNS resolution. If this file is maliciously modified, it could cause the failure or compromise of security functions requiring name resolution, which may include time synchronization, centralized authentication, and remote system logging.
V-22324
medium
The /etc/hosts file (or equivalent) configures local host name to IP address mappings that typically take precedence over DNS resolution. If this file is maliciously modified, it could cause the failure or compromise of security functions requiring name resolution, which may include time synchronization, centralized authentication, and remote system logging.
V-22325
medium
The /etc/hosts file (or equivalent) configures local host name to IP address mappings that typically take precedence over DNS resolution. If this file is maliciously modified, it could cause the failure or compromise of security functions requiring name resolution, which may include time synchronization, centralized authentication, and remote system logging.
V-22326
medium
The /etc/hosts file (or equivalent) configures local host name to IP address mappings that typically take precedence over DNS resolution. If this file is maliciously modified, it could cause the failure or compromise of security functions requiring name resolution, which may include time synchronization, centralized authentication, and remote system logging.
V-22327
medium
The nsswitch.conf file (or equivalent) configures the source of a variety of system security information including account, group, and host lookups. Malicious changes could prevent the system from functioning or compromise system security.
V-22328
medium
The nsswitch.conf file (or equivalent) configures the source of a variety of system security information including account, group, and host lookups. Malicious changes could prevent the system from functioning or compromise system security.
V-22329
medium
The nsswitch.conf file (or equivalent) configures the source of a variety of system security information including account, group, and host lookups. Malicious changes could prevent the system from functioning or compromise system security.
V-22330
medium
The nsswitch.conf file (or equivalent) configures the source of a variety of system security information including account, group, and host lookups. Malicious changes could prevent the system from functioning or compromise system security.
V-22332
medium
The /etc/passwd file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification.
V-22333
medium
The /etc/passwd file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification.
V-22334
medium
File system ACLs can provide access to files beyond what is allowed by the mode numbers of the files. The /etc/passwd file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification.
V-22335
medium
The /etc/group file is critical to system security and must be owned by a privileged user. The group file contains a list of system groups and associated information.
V-22336
medium
The /etc/group file is critical to system security and must be protected from unauthorized modification. The group file contains a list of system groups and associated information.
V-22337
medium
The /etc/group file is critical to system security and must be protected from unauthorized modification. The group file contains a list of system groups and associated information.
V-22338
medium
The /etc/group file is critical to system security and must be protected from unauthorized modification. The group file contains a list of system groups and associated information.
V-22339
medium
The /etc/security/passwd file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification. The file also contains password hashes which must not be accessible to users other than root.
V-22340
medium
The /etc/security/passwd file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification. The file also contains password hashes which must not be accessible to users other than root.
V-22348
medium
Group passwords are typically shared and should not be used. Additionally, if password hashes are readable by non-administrators, the passwords are subject to attack through lookup tables or cryptographic weaknesses in the hashes.
V-22350
low
Excessive permissions on home directories allow unauthorized access to user files.
V-22351
medium
If a user's files are group-owned by a group where the user is not a member, unintended users may be able to access them.
V-22352
medium
Excessive permissions allow unauthorized access to user files.
V-22353
medium
If the startup files are writable by other users, they could modify the startup files to insert malicious commands into the startup files.
V-22354
medium
The library search path environment variable(s) contains a list of directories for the dynamic linker to search to find libraries. If this path includes the current working directory or other relative paths, libraries in these directories may be loaded instead of system libraries. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, two consecutive colons, or a single period, this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths.
V-22355
medium
The library preload list environment variable contains a list of libraries for the dynamic linker to load before loading the libraries required by the binary. If this list contains paths to libraries to the current working directory that have not been authorized, unintended libraries may be preloaded. This variable is formatted as a space-separated list of libraries. Paths starting with a slash (/) are absolute paths.
V-22356
medium
Global initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon.
V-22357
medium
If the skeleton files are not protected, unauthorized personnel could change user startup parameters and possibly jeopardize user files.
V-22358
medium
If the skeleton files are not protected, unauthorized personnel could change user start-up parameters and possibly jeopardize user files.
V-22359
medium
The library search path environment variable(s) contain a list of directories for the dynamic linker to search to find libraries. If this path includes the current working directory or other relative paths, libraries in these directories may be loaded instead of system libraries. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, two consecutive colons, or a single period, this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths.
V-22360
medium
The library preload list environment variable contains a list of libraries for the dynamic linker to load before loading the libraries required by the binary. If this list contains paths to libraries to the current working directory that have not been authorized, unintended libraries may be preloaded. This variable is formatted as a space-separated list of libraries. Paths starting with a slash (/) are absolute paths.
V-22361
medium
Local initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon.
V-22362
medium
Local initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon.
V-22363
medium
The library search path environment variable(s) contain a list of directories for the dynamic linker to search to find libraries. If this path includes the current working directory or other relative paths, libraries in these directories may be loaded instead of system libraries. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, two consecutive colons, or a single period, this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths.
V-22364
medium
The library preload list environment variable contains a list of libraries for the dynamic linker to load before loading the libraries required by the binary. If this list contains paths to libraries to the current working directory that have not been authorized, unintended libraries may be preloaded. This variable is formatted as a space-separated list of libraries. Paths starting with a slash (/) are absolute paths.
V-22365
medium
If shell files are group-owned by users other than root or a system group, they could be modified by intruders or malicious users to perform unauthorized actions.
V-22366
medium
Shells with world/group write permissions give the ability to maliciously modify the shell to obtain unauthorized access.
V-22367
medium
File system ACLs can provide access to files beyond what is allowed by the mode numbers of the files.
V-22368
medium
The nodev (or equivalent) mount option causes the system to not handle device files as system devices. This option must be used for mounting any file system not containing approved device files. Device files can provide direct access to system hardware and can compromise security if not protected.
V-22369
medium
If a user can write to the audit logs, then audit trails can be modified or destroyed and system intrusion may not be detected.
V-22370
low
To prevent unauthorized access or manipulation of system audit logs, the tools for manipulating those logs must be protected.
V-22371
low
To prevent unauthorized access or manipulation of system audit logs, the tools for manipulating those logs must be protected.
V-22372
low
To prevent unauthorized access or manipulation of system audit logs, the tools for manipulating those logs must be protected.
V-22373
low
To prevent unauthorized access or manipulation of system audit logs, the tools for manipulating those logs must be protected.
V-22376
low
If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises, and damages incurred during a system compromise.
V-22377
low
If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.
V-22378
low
If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.
V-22382
low
If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.
V-22383
medium
Actions concerning dynamic kernel modules must be recorded as they are substantial events. Dynamic kernel modules can increase the attack surface of a system. A malicious kernel module can be used to substantially alter the functioning of a system, often with the purpose of hiding a compromise from the SA.
V-22384
medium
A cron.allow file that is readable and/or writable by other than root could allow potential intruders and malicious users to use the file contents to help discern information, such as who is allowed to execute cron programs, which could be harmful to overall system and network security.
V-22385
medium
To protect the integrity of scheduled system jobs and prevent malicious modification to these jobs, crontab files must be secured.
V-22386
medium
To protect the integrity of scheduled system jobs and to prevent malicious modification to these jobs, crontab files must be secured. ACLs on crontab files may provide unauthorized access to the files.
V-22387
medium
To protect the integrity of scheduled system jobs and to prevent malicious modification to these jobs, crontab files must be secured. ACLs on cron and crontab directories may provide unauthorized access to these directories. Unauthorized modifications to these directories or their contents may result in the addition of unauthorized cron jobs or deny service to authorized cron jobs.

V-22388
medium
Cron logs contain reports of scheduled system activities and must be protected from unauthorized access or manipulation.
V-22389
medium
If there are excessive file permissions for the cron.deny file, sensitive information could be viewed or edited by unauthorized users.
V-22390
medium
File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. Unauthorized modification of the at.allow file could result in Denial of Service to authorized at users and the granting of the ability to run at jobs to unauthorized users.
V-22391
medium
If the group of the cron.allow is not set to system, bin, sys, or cron, the possibility exists for an unauthorized user to view or edit the list of users permitted to use cron. Unauthorized modification of this file could cause Denial of Service to authorized cron users or provide unauthorized users with the ability to run cron jobs.

V-22392
medium
The at daemon control files restrict access to scheduled job manipulation and must be protected. Unauthorized modification of the at.deny file could result in Denial of Service to authorized at users or provide unauthorized users with the ability to run at jobs.
V-22393
medium
The at daemon control files restrict access to scheduled job manipulation and must be protected. Unauthorized modification of the at.deny file could result in Denial of Service to authorized at users or provide unauthorized users with the ability to run at jobs.
V-22394
medium
Cron daemon control files restrict the scheduling of automated tasks and must be protected. Unauthorized modification of the cron.deny file could result in Denial of Service to authorized cron users or could provide unauthorized users with the ability to run cron jobs.
V-22395
medium
If the at directory has an extended ACL, unauthorized users could be allowed to view or to edit files containing sensitive information within the at directory. Unauthorized modifications could result in Denial of Service to authorized at jobs.
V-22396
medium
If the group of the "at" directory is not system, bin, sys, or cron, unauthorized users could be allowed to view or edit files containing sensitive information within the directory.
V-22397
medium
If the group-owner of the at.allow file is not set to system, bin, sys, or cron, unauthorized users could be allowed to view or edit the list of users permitted to run at jobs. Unauthorized modification could result in Denial of Service to authorized at users or provide unauthorized users with the ability to run at jobs.
V-22398
medium
If the group owner of the at.deny file is not set to system, bin, sys, or cron, unauthorized users could be allowed to view or edit sensitive information contained within the file. Unauthorized modification could result in Denial of Service to authorized at users or provide unauthorized users with the ability to run at jobs.
V-22404
medium
Kernel core dumps may contain the full contents of system memory at the time of the crash. Kernel core dumps may consume a considerable amount of disk space and may result in Denial of Service by exhausting the available space on the target file system. The kernel core dump process may increase the amount of time a system is unavailable due to a crash. Kernel core dumps can be useful for kernel debugging.

V-22405
low
Kernel core dumps may contain the full contents of system memory at the time of the crash. As the system memory may contain sensitive information, it must be protected accordingly. If the kernel core dump data directory is not group-owned by a system group, the core dumps contained in the directory may be subject to unauthorized access.
V-22406
low
Kernel core dumps may contain the full contents of system memory at the time of the crash. As the system memory may contain sensitive information, it must be protected accordingly. If the mode of the kernel core dump data directory is more permissive than 0700, unauthorized users may be able to view or to modify kernel core dump data files.
V-22407
low
Kernel core dumps may contain the full contents of system memory at the time of the crash. As the system memory may contain sensitive information, it must be protected accordingly. If there is an extended ACL for the kernel core dump data directory, unauthorized users may be able to view or to modify kernel core dump data files.
V-22409
low
The processing of Internet Control Message Protocol (ICMP) timestamp requests increases the attack surface of the system.
V-22410
medium
Responding to broadcast Internet Control Message Protocol (ICMP) echoes facilitates network mapping and provides a vector for amplification attacks.
V-22411
medium
The processing of Internet Control Message Protocol (ICMP) timestamp requests increases the attack surface of the system. Responding to broadcast ICMP timestamp requests facilitates network mapping and provides a vector for amplification attacks.
V-22412
medium
Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures.
V-22413
medium
Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures.
V-22414
medium
Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the handling of source-routed traffic destined to the system itself, not to traffic forwarded by the system to another, such as when IPv4 forwarding is enabled and the system is functioning as a router
V-22415
medium
Proxy ARP allows a system to respond to ARP requests on one interface on behalf of hosts connected to another interface. If this function is enabled when not required, addressing information may be leaked between the attached network segments.
V-22416
medium
ICMP redirect messages are used by routers to inform hosts a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.

V-22417
medium
ICMP redirect messages are used by routers to inform hosts a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology.
V-22418
low
Martian packets are packets containing addresses known by the system to be invalid. Logging these messages allows the SA to identify misconfigurations or attacks in progress.
V-22419
medium
A TCP SYN flood attack can cause Denial of Service by filling a system's TCP connection table with connections in the SYN_RCVD state. Syncookies are a mechanism used to not track a connection until a subsequent ACK is received, verifying the initiator is attempting a valid connection and is not a flood source. This technique does not operate in a fully standards-compliant manner, but is only activated when a flood condition is detected, and allows defense of the system while continuing to service valid requests.
V-22422
low
File system journaling, or logging, can allow reconstruction of file system data after a system crash, thus preserving the integrity of data that may have otherwise been lost. Journaling file systems typically do not require consistency checks upon booting after a crash, which can improve system availability. Some file systems employ other mechanisms to ensure consistency which also satisfy this requirement.
V-22423
medium
Failure to give ownership of sensitive files or utilities to system groups may provide unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.
V-22424
medium
The Internet service daemon configuration files must be protected as malicious modification could cause Denial of Service or increase the attack surface of the system.
V-22427
medium
Failure to give ownership of system configuration files to root or a system group provides the designated owner and unauthorized users with the potential to change the system configuration which could weaken the system's security posture.
V-22428
medium
The services file is critical to the proper operation of network services and must be protected from unauthorized modification. If the services file has an extended ACL, it may be possible for unauthorized users to modify the file. Unauthorized modification could result in the failure of network services.
V-22429
medium
The portmap and rpcbind services increase the attack surface of the system and should only be used when needed. The portmap or rpcbind services are used by a variety of services using Remote Procedure Calls (RPCs).
V-22430
medium
The portmap and rpcbind services increase the attack surface of the system and should only be used when needed. The portmap or rpcbind services are used by a variety of services using Remote Procedure Calls (RPCs).
V-22432
medium
The rlogind process provides a typically unencrypted, host-authenticated remote access service. SSH should be used in place of this service.
V-22435
medium
Failure to give group ownership of the hosts.lpd file to bin, sys, or system provides the members of the owning group and possible unauthorized users, with the potential to modify the hosts.lpd file. Unauthorized modifications could disrupt access to local printers from authorized remote hosts or permit unauthorized remote access to local printers.
V-22436
medium
Excessive permissions on the hosts.lpd (or equivalent) file may permit unauthorized modification. Unauthorized modifications could disrupt access to local printers from authorized remote hosts or permit unauthorized remote access to local printers.
V-22437
medium
If an extended ACL exists on the traceroute executable file, it may provide unauthorized users with access to the file. Malicious code could be inserted by an attacker and triggered whenever the traceroute command is executed by authorized users. Additionally, if an unauthorized user is granted executable permissions to the traceroute command, it could be used to gain information about the network topology behind the firewall. This information may allow an attacker to determine trusted routers and other network information possibly leading to system and network compromise.
V-22438
medium
If the alias file is not group-owned by a system group, an unauthorized user may modify the file to add aliases to run malicious code or redirect e-mail.
V-22439
medium
Excessive permissions on the aliases file may permit unauthorized modification. If the alias file is modified by an unauthorized user, they may modify the file to run malicious code or redirect e-mail.
V-22440
medium
If a file executed through a mail aliases file is not group-owned by root or a system group, it may be subject to unauthorized modification. Unauthorized modification of files executed through aliases may allow unauthorized users to attain root privileges.
V-22441
medium
Excessive permissions on files executed through a mail alias file could result in modification by an unauthorized user, execution of malicious code, and/or system compromise.
V-22442
medium
If the SMTP service log file has an extended ACL, unauthorized users may be allowed to access or to modify the log file.
V-22444
medium
If the ftpusers file is not group-owned by a system group, an unauthorized user may modify the file to allow unauthorized accounts to use FTP.
V-22445
medium
Excessive permissions on the ftpusers file could permit unauthorized modification. Unauthorized modification could result in Denial of Service to authorized FTP users or permit unauthorized users to access the FTP service.
V-22446
medium
.Xauthority files ensure the user is authorized to access that specific X Windows host. Extended ACLs may permit unauthorized modification of these files, which could lead to Denial of Service to authorized access or allow unauthorized access to be obtained.
V-22447
medium
SNMP Versions 1 and 2 are not considered secure. Without the strong authentication and privacy provided by the SNMP Version 3 User-based Security Model (USM), an attacker or other unauthorized users may gain access to detailed system management information and use the information to launch attacks against the system.
V-22448
medium
The SNMP service must use SHA-1 or a FIPS 140-2 approved successor for authentication and integrity.
V-22450
medium
The ability to read the MIB file could impart special knowledge to an intruder or malicious user about the ability to extract compromising information about the system or network.
V-22451
medium
The snmpd.conf file contains authenticators and must be protected from unauthorized access and modification. If the file is not group-owned by a system group, it may be subject to access and modification from unauthorized users.
V-22452
medium
The snmpd.conf file contains authenticators and must be protected from unauthorized access and modification.
V-22453
medium
Unauthorized users must not be allowed to access or modify the /etc/syslog.conf file.
V-22454
medium
Unauthorized users must not be allowed to access or modify the /etc/syslog.conf file.
V-22455
medium
A syslog server (log host) receives syslog messages from one or more systems. This data can be used as an authoritative log source in the event a system is compromised and its local logs are suspect.
V-22456
medium
SSHv1 is not a DoD-approved protocol and has many well-known vulnerability exploits. Exploits of the SSH client could provide access to the system with the privileges of the user running the client.
V-22457
medium
The SSH daemon should only listen on network addresses designated for management traffic. If the system has multiple network interfaces and SSH listens on addresses not designated for management traffic, the SSH service could be subject to unauthorized access. If SSH is used for purposes other than management, such as providing an SFTP service, the list of approved listening addresses may be documented.
V-22458
medium
DoD information systems are required to use FIPS 140-2 approved ciphers. SSHv2 ciphers meeting this requirement are 3DES and AES.
V-22459
medium
The Cipher-Block Chaining (CBC) mode of encryption as implemented in the SSHv2 protocol is vulnerable to chosen plain text attacks and must not be used.

V-22460
medium
DoD information systems are required to use FIPS 140-2 approved cryptographic hash functions.
V-22461
medium
DoD information systems are required to use FIPS 140-2 approved ciphers. SSHv2 ciphers meeting this requirement are 3DES and AES.
V-22462
medium
The Cipher-Block Chaining (CBC) mode of encryption as implemented in the SSHv2 protocol is vulnerable to chosen plain text attacks and must not be used.
V-22463
medium
DoD information systems are required to use FIPS 140-2 approved cryptographic hash functions.
V-22470
medium
Restricting SSH logins to a limited group of users, such as system administrators, prevents password-guessing and other SSH attacks from reaching system accounts and other accounts not authorized for SSH access.
V-22471
medium
If a public host key file is modified by an unauthorized user, the SSH service may be compromised.
V-22472
medium
If an unauthorized user obtains the private SSH host key file, the host could be impersonated.
V-22473
low
GSSAPI authentication is used to provide additional authentication mechanisms to applications. Allowing GSSAPI authentication through SSH exposes the system’s GSSAPI to remote hosts, increasing the attack surface of the system. GSSAPI authentication must be disabled unless needed.
V-22474
low
GSSAPI authentication is used to provide additional authentication mechanisms to applications. Allowing GSSAPI authentication through SSH exposes the system’s GSSAPI to remote hosts, increasing the attack surface of the system. GSSAPI authentication must be disabled unless needed.
V-22475
low
Kerberos authentication for SSH is often implemented using GSSAPI. If Kerberos is enabled through SSH, the SSH daemon provides a means of access to the system's Kerberos implementation. Vulnerabilities in the system's Kerberos implementation may then be subject to exploitation. To reduce the attack surface of the system, the Kerberos authentication mechanism within SSH must be disabled for systems not using this capability.
V-22482
low
The SSH protocol has the ability to provide multiple sessions over a single connection without reauthentication. A compromised client could use this feature to establish additional sessions to a system without consent or knowledge of the user.

Alternate per-connection session limits may be documented if needed for a valid mission requirement. Greater limits are expected to be necessary in situations where TCP or X11 forwarding are used.
V-22485
medium
If other users have access to modify user-specific SSH configuration files, they may be able to log into the system as another user.
V-22486
medium
SSH daemon privilege separation causes the SSH process to drop root privileges when not needed, which would decrease the impact of software vulnerabilities in the unprivileged section.
V-22487
medium
If SSH permits rhosts RSA authentication, a user may be able to log in based on the keys of the host originating the request and not any user-specific authentication.
V-22488
medium
If compression is allowed in an SSH connection prior to authentication, vulnerabilities in the compression software could result in compromise of the system from an unauthenticated connection, potentially with root privileges.
V-22489
medium
Failure to display the DoD logon banner prior to a log in attempt will negate legal proceedings resulting from unauthorized access to system resources.

The SSH service must be configured to display the DoD logon warning banner either through the SSH configuration or a wrapper program, such as TCP_WRAPPERS.

The SSH daemon may also be used to provide SFTP service. The warning banner configuration for SSH will apply to SFTP.
V-22490
medium
If a system has no default gateway defined, the system is at increased risk of man-in-the-middle, monitoring, and Denial of Service attacks.
V-22491
medium
If the system is configured for IP forwarding and is not a designated router, it could be used to bypass network security by providing a path for communication not filtered by network devices.
V-22492
medium
Failure to give group ownership of the NFS export configuration file to root or a system group provides the designated group owner and possible unauthorized users with the potential to change system configuration which could weaken the system's security posture.
V-22493
low
File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. Excessive permissions on the NFS export configuration file could allow unauthorized modification of the file, which could result in Denial of Service to authorized NFS exports and the creation of additional unauthorized exports.
V-22496
medium
Failure to give group ownership of sensitive files or directories to root provides the members of the owning group with the potential to access sensitive information or change system configuration which could weaken the system's security posture.
V-22497
medium
Excessive permissions could endanger the security of the Samba configuration file and, ultimately, the system and network.
V-22498
medium
If the permissions of the smbpasswd file are too permissive, the smbpasswd file may be maliciously accessed or modified, potentially resulting in the compromise of Samba accounts.
V-22499
medium
Samba share authentication does not provide for individual user identification and must not be used.
V-22500
medium
Samba must be configured to protect authenticators. If Samba passwords are not encrypted for storage, plain-text user passwords may be read by those with access to the Samba password file.
V-22501
medium
Guest access to shares permits anonymous access and is not permitted.
V-22502
medium
File system extended ACLs provide access to files beyond what is allowed by the numbers of the files. Excessive permissions on the hosts.nntp file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users.
V-22503
medium
File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. Excessive permissions on the hosts.nntp.nolimit file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users.
V-22504
medium
File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. Excessive permissions on the nnrp.access file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users.
V-22505
medium
Extended ACLs may provide excessive permissions on the /etc/news/passwd.nntp file, which may permit unauthorized access or modification to the NNTP configuration.
V-22506
medium
Verification using the system package management tool can be used to determine that system software has not been tampered with.

This requirement is not applicable to systems that do not use package management tools.
V-22507
low
ACLs can provide permissions beyond those permitted through the file mode and must be verified by file integrity tools.
V-22508
low
Extended attributes in file systems are used to contain arbitrary data and file metadata with security implications.
V-22509
low
File integrity tools often use cryptographic hashes for verifying that file contents have not been altered. These hashes must be FIPS 140-2 approved.
V-22511
medium
The Stream Control Transmission Protocol (SCTP) is an IETF-standardized transport layer protocol. This protocol is not yet widely used. Binding this protocol to the network stack increases the attack surface of the host. Unprivileged local processes may be able to cause the system to dynamically load a protocol handler by opening a socket using the protocol.
V-22530
medium
The Reliable Datagram Sockets (RDS) protocol is a relatively new protocol developed by Oracle for communication between the nodes of a cluster. Binding this protocol to the network stack increases the attack surface of the host. Unprivileged local processes may be able to cause the system to dynamically load a protocol handler by opening a socket using the protocol.
V-22544
medium
Proxy Neighbor Discovery Protocol (NDP) allows a system to respond to NDP requests on one interface on behalf of hosts connected to another interface. If this function is enabled when not required, addressing information may be leaked between the attached network segments.
V-22545
medium
6to4 is an IPv6 transition mechanism involving tunneling IPv6 packets encapsulated in IPv4 packets on an ad-hoc basis. This is not a preferred transition strategy and increases the attack surface of the system.
V-22547
medium
IP tunneling mechanisms can be used to bypass network filtering.
V-22548
medium
DHCP allows for the unauthenticated configuration of network parameters on the system by exchanging information with a DHCP server.
V-22549
medium
Dynamic DNS updates transmit unencrypted information about a system including its name and address and should not be used unless needed.
V-22550
medium
ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.
V-22551
medium
ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table that could reveal portions of the network topology.
V-22552
medium
Reverse-path filtering provides protection against spoofed source addresses by causing the system to discard packets that have source addresses for which the system has no route or if the route does not point towards the interface on which the packet arrived. Depending on the role of the system, reverse-path filtering may cause legitimate traffic to be discarded and, therefore, should be used with a more permissive mode or filter, or not at all. Whenever possible, reverse-path filtering should be used.
V-22553
medium
Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when IPv6 forwarding is enabled and the system is functioning as a router.
V-22554
medium
Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the handling of source-routed traffic destined to the system itself, not to traffic forwarded by the system to another, such as when IPv6 forwarding is enabled and the system is functioning as a router.
V-22556
medium
LDAP can be used to provide user authentication and account information, which are vital to system security. Communication between an LDAP server and a host using LDAP requires authentication.
V-22557
medium
The NSS LDAP service provides user mappings which are a vital component of system security. Communication between an LDAP server and a host using LDAP for NSS require authentication.
V-22559
medium
LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.
V-22560
medium
LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.
V-22561
medium
LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.
V-22562
medium
LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.
V-22563
medium
LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.
V-22564
medium
LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.
V-22565
medium
LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.
V-22566
medium
LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification.
V-22576
low
Successful exploitation of buffer overflow vulnerabilities relies in some measure to having a predictable address structure of the executing program. Address randomization techniques reduce the probability of a successful exploit.
V-22577
low
Automated file system mounting tools may provide unprivileged users with the ability to access local media and network shares. If this access is not necessary for the system’s operation, it must be disabled to reduce the risk of unauthorized access to these resources.
V-22578
low
USB is a common computer peripheral interface. USB devices may include storage devices that could be used to install malicious software on a system or exfiltrate data.
V-22579
low
USB is a common computer peripheral interface. USB devices may include storage devices that could be used to install malicious software on a system or exfiltrate data.
V-22582
medium
A local firewall protects the system from exposing unnecessary or undocumented network services to the local enclave. If a system within the enclave is compromised, firewall protection on an individual system continues to protect it from attack.
V-22583
medium
A local firewall protects the system from exposing unnecessary or undocumented network services to the local enclave. If a system within the enclave is compromised, firewall protection on an individual system continues to protect it from attack.
V-22665
medium
Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this software is used when not required, system network information may be unnecessarily transmitted across the network.
V-22702
medium
Sensitive system and user information could provide a malicious user with enough information to penetrate further into the system.
V-23732
medium
Failure to display the login banner prior to a logon attempt will negate legal proceedings resulting from unauthorized access to system resources.

NOTE: SFTP and FTPS are encrypted alternatives to FTP and should be used in place of FTP. SFTP is implemented by the SSH service and uses its banner configuration.
V-23736
low
The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing.
V-23738
low
The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing.
V-23739
low
The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing.
V-23741
medium
To provide some mitigation to TCP DoS attacks, the clear_partial_conns parameter must be enabled.
V-23952
medium
If unrestricted mail relaying is permitted, unauthorized senders could use this host as a mail relay for the purpose of sending SPAM or other unauthorized activity.
V-23953
medium
The ldd command provides a list of dependent libraries needed by a given binary, which is useful for troubleshooting software. Instead of parsing the binary file, some ldd implementations invoke the program with a special environment variable set, which causes the system dynamic linker to display the list of libraries. Specially crafted binaries can specify an alternate dynamic linker which may cause a program to be executed instead of examined. If the program is from an untrusted source, such as in a user home directory, or a file suspected of involvement in a system compromise, unauthorized software may be executed with the rights of the user running ldd.

Some ldd implementations include protections preventing the execution of untrusted files. If such protections exist, this requirement is not applicable.

An acceptable method of disabling ldd is changing its mode to 0000. The SA may conduct troubleshooting by temporarily changing the mode to allow execution and running the ldd command as an unprivileged user upon trusted system binaries.
V-23972
medium
Responding to broadcast ICMP echo requests facilitates network mapping and provides a vector for amplification attacks.
V-24331
medium
Failure to display the login banner prior to a logon attempt will negate legal proceedings resulting from unauthorized access to system resources.

This requirement applies to graphical desktop environments provided by the system to locally attached displays and input devices, as well as, to graphical desktop environments provided to remote systems, including thin clients.
V-24347
medium
In accordance with CTO 07-015, PKI authentication is required. This provides stronger, two-factor authentication than using a username/password.

NOTE: The following are exempt from this; however, they must meet all password requirements and must be documented with the IAO:

- Stand-alone systems.
- Application Accounts.
- Students or unpaid employees (such as interns) who are not eligible to receive or not in receipt of a CAC, PIV, or ALT.
- Warfighters and support personnel located at operational tactical locations conducting wartime operations that are not "collocated" with RAPIDS workstations to issue CAC, are not eligible for CAC, or do not have the capability to use ALT.
- Test systems with an Interim Approval to Test (IATT) and provide protection via separate VPN, firewall, or security measures preventing access to network and system components from outside the protection boundary documented in the IATT.
V-24357
low
Audit records contain evidence that can be used in the investigation of compromised systems. To prevent this evidence from compromise, it must be sent to a separate system continuously. Methods for sending audit records include, but are not limited to, system audit tools used to send logs directly to another host or through the system's syslog service to another host.
V-24384
medium
The authentication of automated LDAP connections between systems must not use passwords since more secure methods are available, such as PKI and Kerberos. Additionally, the storage of unencrypted passwords on the system is not permitted.
V-24386
high
The telnet daemon provides a typically unencrypted remote access service which does not provide for the confidentiality and integrity of user passwords or the remote session. If a privileged user were to log on using this service, the privileged user password could be compromised.
V-29491
medium
The /etc/netsvc.conf file is used to specify the ordering of name resolution for the sendmail command, alias resolution for the sendmail command, and host name resolution routines. Malicious changes could prevent the system from functioning correctly or compromise system security.
V-29492
medium
The /etc/netsvc.conf file is used to specify the ordering of name resolution for the sendmail command, alias resolution for the sendmail command, and host name resolution routines. Malicious changes could prevent the system from functioning correctly or compromise system security.
V-29493
medium
The /etc/netsvc.conf file is used to specify the ordering of name resolution for the sendmail command, alias resolution for the sendmail command, and host name resolution routines. Malicious changes could prevent the system from functioning correctly or compromise system security.
V-29494
medium
The /etc/netsvc.conf file is used to specify the ordering of name resolution for the sendmail command, alias resolution for the sendmail command, and host name resolution routines. Malicious changes could prevent the system from functioning correctly or compromise system security.
V-29495
medium
Disabling directed broadcast prevents packets directed to a gateway to be broadcasted on a remote network.
V-29496
medium
The ICMP attacks may be of the form of ICMP source quench attacks and Path MTU Discovery (PMTUD) attacks. If this network option tcp_icmpsecure is turned on, the system does not react to ICMP source quench messages. This will protect against ICMP source quench attacks. The payload of the ICMP message is tested to determine if the sequence number of the TCP header portion of the payload is within the range of acceptable sequence numbers. This will mitigate PMTUD attacks to a large extent.
V-29497
medium
The tcp_tcpsecure parameter provides protection for TCP connections from fake SYN's, fake RST, and data injections on established connections. The first vulnerability involves sending a fake SYN to an established connection to abort the connection. The second vulnerability involves sending a fake RST to an established connection to abort the connection. The third vulnerability involves injecting fake data in an established TCP connection.
V-29498
medium
The parameter ip_nfrag provides an additional layer of protection against IP fragmentation attacks. The value the ip_nfrag specifies is the maximum number of fragments of an IP packet that can be kept in the IP reassembly queue at any time. The default value of this network option is 200. This is a reasonable value for most environments and offers protection from IP fragmentation attacks.
V-29499
medium
The bootp service is used for Network Installation Management (NIM) and remote booting of systems. The bootp service should not be active unless it is needed for NIM servers or booting remote systems. Running unnecessary services increases the attack vector of the system.
V-29500
medium
When contacted, chargen responds with some random characters. When contacted via UDP, it
will respond with a single UDP packet. When contacted via TCP, it will continue spewing characters until the client closes the connection. An easy attack is 'ping-pong' in which an attacker spoofs a packet between two machines running chargen. This will cause them to spew characters at each other, slowing the machines down and saturating the network.
The chargen service is unnecessary and provides an opportunity for Denial of Service attack.
V-29501
medium
The CMSD service for CDE is an unnecessary process that runs a root and increases attack vector of the system. Buffer overflow attacks against the CMSD process can potentially give access to the system.
V-29502
medium
The ttdbserver service for CDE is an unnecessary service that runs as root and might be compromised.
V-29503
medium
The comsat daemon notifies users on incoming email. This is an unnecessary service and is vulnerable to a flood attack. Running unnecessary services increases the attack vector of the system.
V-29504
medium
The daytime service runs as root from the inetd daemon and can provide an opportunity for Denial of Service PING or PING-PONG attacks. The daytime service is unnecessary and it increases the attack vector of the system.
V-29505
medium
The discard service runs as root from the inetd server and can be used in Denial of Service attacks. The discard service is unnecessary and it increases the attack vector of the system.
V-29506
medium
This service is started automatically by the inetd daemon with root permission in response to a CDE client requesting a process to be started on the daemon’s host system. Running the dtscp service is unnecessary and it increases the attack vector of the system.
V-29507
medium
The echo service can be used in Denial of Service or SMURF attacks. It can also used at someone else to get through a firewall or start a data storm. The echo service is unnecessary and it increases the attack vector of the system.
V-29508
medium
The IMAP service should not be running unless the system is acting as a mail server for client connections. Running unnecessary services increases the attack vector on the system.
V-29509
medium
The POP3 service is only needed if the server is acting as a mail server and clients are using applications that only support POP3. Users' ids and passwords are sent in plain text to the POP3 service. If mail client access is needed, consider using IMAP or SSL enabled POP3.
V-29510
medium
The talk and ntalk commands allow users on the same or different systems on converse. The talk daemons are started from the inetd process and run as root. These unnecessary processes increase the attack vector of the system and may cause Denial of Service by scrambling the users display.
V-29511
medium
The netstat service can potentially give out network information on active connections if it is running. The information given out can aid in an attack and weaken the systems defensive posture.
V-29512
medium
The PCNFS service predates Microsoft’s SMB specifications. If a similar service is needed to share files from a Windows based OS to a UNIX based OS, consider SAMBA.
V-29513
medium
The systat daemon allows remote users to see the running process and who is running them. This may aid in information collection for an attack and weaken the security posture of the system.
V-29514
medium
The time service is an internal inetd function is used by the rdate command. This service is sometimes used to synchronize clocks at boot time. The service is outdated. Use the ntpdate command instead.
V-29515
medium
The rusersd daemon gives out a list of current uses on the system. The rusersd daemon is unnecessary and it increases the attack vector of the system by providing information on the current users of the system.
V-29516
medium
The sprayd service is sometimes used for network and nfs troubleshooting. The spray service can be used for both buffer overflow and Denial of Service attacks by saturating the network. The sprayd daemon is an unnecessary service.
V-29517
medium
The rstatd can give out information on the running system, such as the CPU usage, the system uptime, its network usage, and other system information that could potentially aid in an attack. The rstatd service is unnecessary and it weakens the defensive posture of the system. If systems monitoring is needed, use a third party tool or SNMP.
V-29518
medium
Running Xservers and X-login managers when not needed for X11 session management increases the attack vector of the system by running unnecessary services.
V-29519
medium
The ftpaccess.ctl file contains options for the ftp daemon, such as herald, motd, user access, and permissions to files and directories. If the ftpaccess.ctl file does not exist, the ftpd process will not display any warning banners, and permissions will only be enforced using basic UNIX permissions.
V-29520
medium
If the ftpaccess.ctl file is not owned by root, an unauthorized user may modify the file to allow unauthorized access to change the file. Unauthorized modification could result in Denial of Service to authorized FTP users or permit unauthorized access to system information.

V-29521
medium
If the ftpaccess.ctl file is not group-owned by a system group, an unauthorized user may modify the file to allow unauthorized access to modify the file. Unauthorized modification could result in Denial of Service to authorized FTP users or permit unauthorized access to system information.
V-29522
medium
Excessive permissions on the ftpaccess.ctl file could permit unauthorized modification. Unauthorized modification could result in Denial of Service to authorized FTP users or permit unauthorized access to system information.
V-29523
medium
Excessive permissions on the ftpaccess.ctl file could permit unauthorized modification. Unauthorized modification could result in Denial of Service to authorized FTP users or permit unauthorized access to system information.
V-4083
medium
If graphical desktop sessions do not lock the session after 15 minutes of inactivity, requiring re-authentication to resume operations, the system or individual data could be compromised by an alert intruder who could exploit the oversight. This requirement applies to graphical desktop environments provided by the system to locally attached displays and input devices, as well as, to graphical desktop environments provided to remote systems, including thin clients.
V-4084
medium
If a user, or root, used the same password continuously or was allowed to change it back shortly after being forced to change it to something else, it would provide a potential intruder with the opportunity to keep guessing at one user's password until it was guessed correctly.
V-4087
medium
If start-up files execute world-writable programs, especially in unprotected directories, they could be maliciously modified to become Trojans destroying user files or otherwise compromising the system at the user, or higher, level. If the system is compromised at the user level, it is much easier to eventually compromise the system at the root and network level.
V-4089
medium
System start-up files not owned by root could lead to system compromise by allowing malicious users or applications to modify them for unauthorized purposes. This could lead to system and network compromise.
V-4090
medium
If system start-up files do not have a group owner of a system group, the files may be modified by malicious users or intruders.
V-4091
medium
System start-up files executing programs owned by other than root (or another privileged user) or an application indicate the system may have been compromised.
V-4246
medium
A system's BIOS or system controller handles the initial startup of a system and its configuration must be protected from unauthorized modification. When the BIOS or system controller supports the creation of user accounts or passwords, such protections must be used and accounts/passwords only assigned to system administrators. Failure to protect BIOS or system controller settings could result in Denial of Service or compromise of the system resulting from unauthorized configuration changes.
V-4247
high
Malicious users with removable boot media can gain access to a system configured to use removable media as the boot loader.
V-4255
high
Storing the boot loader on removable media in an insecure location could allow a malicious user to modify the systems boot instructions or boot to an insecure operating system.
V-4269
medium
Accounts providing no operational purpose provide additional opportunities for system compromise. Unnecessary accounts include user accounts for individuals not requiring access to the system and application accounts for applications not installed on the system.
V-4273
medium
Excessive permissions on the hosts.nntp file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users.
V-4274
medium
Excessive permissions on the hosts.nntp.nolimit file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users.
V-4275
medium
Excessive permissions on the nnrp.access file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users.
V-4276
medium
File permissions more permissive than 0600 for /etc/news/passwd.nntp may allow access to privileged information by system intruders or malicious users.
V-4277
medium
If critical system files are not owned by a privileged user, system integrity could be compromised.
V-4278
medium
If critical system files do not have a privileged group owner, system integrity could be compromised.
V-4284
medium
The AIX securetcpip command disables insecure network utilities, such as rcp, rlogin, rlogind, rsh, rshd, tftp, tftpd, and trpt/d. These services increase the attack surface of the system.
V-4287
medium
If a baseline of files with the TCB bit set is not kept and checked weekly, the system could be compromised without the knowledge of any authority.
V-4295
high
SSHv1 is not a DoD-approved protocol and has many well-known vulnerability exploits. Exploits of the SSH daemon could provide immediate root access to the system.
V-4298
medium
The remote console feature provides an additional means of access to the system which could allow unauthorized access if not disabled or properly secured. With virtualization technologies, remote console access is essential as there is no physical console for virtual machines. Remote console access must be protected in the same manner as any other remote privileged access method.
V-4301
medium
To assure the accuracy of the system clock, it must be synchronized with an authoritative time source within DoD. Many system functions, including time-based login and activity restrictions, automated reports, system logs, and audit records, depend on an accurate system clock. If there is no confidence in the correctness of the system clock, time-based functions may not operate as intended and records may be of diminished value.

Authoritative time sources include authorized time servers within the enclave synchronizing with upstream authoritative sources. Specific requirements for the upstream synchronization of Network Time Protocol (NTP) servers are covered in the Network Other Devices STIG.

For systems located on isolated or closed networks, it is not necessary to synchronize with a global authoritative time source. If a global authoritative time source is not available to systems on an isolated network, a local authoritative time source must be established on this network and used by the systems connected to this network. This is necessary to provide the ability to correlate events and allow for the correct operation of time-dependent protocols between systems on the isolated network.

If the system is completely isolated (no connections to networks or other systems), time synchronization is not required as no correlation of events between systems will be necessary. If the system is completely isolated, this requirement is not applicable.
V-4304
medium
File system journaling, or logging, can allow reconstruction of file system data after a system crash, thus, preserving the integrity of data that may have otherwise been lost. Journaling file systems typically do not require consistency checks upon booting after a crash, which can improve system availability. Some file systems employ other mechanisms to ensure consistency which also satisfy this requirement.
V-4321
medium
Samba is a tool used for the sharing of files and printers between Windows and UNIX operating systems. It provides access to sensitive files and, therefore, poses a security risk if compromised.
V-4357
medium
Rotate audit logs daily to preserve audit file system space and to conform to the DoD/DISA requirement. If it is not rotated daily and moved to another location, then there is more of a chance for the compromise of audit data by malicious users.
V-4358
medium
If file permissions for cron.deny are more permissive than 0600, sensitive information could be viewed or edited by unauthorized users.
V-4360
low
The umask controls the default access mode assigned to newly created files. An umask of 077 limits new files to mode 700 or less permissive. Although umask is often represented as a 4-digit octal number, the first digit representing special access modes is typically ignored or required to be 0.
V-4361
medium
If the owner of the cron.allow file is not set to root, bin, or sys, the possibility exists for an unauthorized user to view or to edit sensitive information.
V-4364
medium
If the at directory has a mode more permissive than 0755, unauthorized users could be allowed to view or to edit files containing sensitive information within the at directory. Unauthorized modifications could result in Denial of Service to authorized at jobs.
V-4365
medium
If the owner of the at directory is not root, bin, sys, daemon, or cron unauthorized users could be allowed to view or edit files containing sensitive information within the directory.
V-4366
medium
The umask controls the default access mode assigned to newly created files. An umask of 077 limits new files to mode 700 or less permissive. Although umask is often represented as a 4-digit number, the first digit representing special access modes is typically ignored or required to be 0.
V-4367
medium
If the owner of the at.allow file is not set to root, bin, or sys, unauthorized users could be allowed to view or edit sensitive information contained within the file.
V-4368
medium
If the owner of the at.deny file is not set to root, bin, or sys, unauthorized users could be allowed to view or edit sensitive information contained within the file.
V-4369
medium
If the traceroute command owner has not been set to root, an unauthorized user could use this command to obtain knowledge of the network topology inside the firewall. This information may allow an attacker to determine trusted routers and other network information possibly leading to system and network compromise.
V-4370
medium
If the group owner of the traceroute command has not been set to a system group, unauthorized users could have access to the command and use it to gain information regarding a network's topology inside of the firewall. This information may allow an attacker to determine trusted routers and other network information possibly leading to system and network compromise.
V-4371
medium
If the mode of the traceroute executable is more permissive than 0700, malicious code could be inserted by an attacker and triggered whenever the traceroute command is executed by authorized users. Additionally, if an unauthorized user is granted executable permissions to the traceroute command, it could be used to gain information about the network topology behind the firewall. This information may allow an attacker to determine trusted routers and other network information possibly leading to system and network compromise.
V-4382
high
If a web browser flaw is exploited while running as a privileged user, the entire system could be compromised.

Specific exceptions for local service administration should be documented in site-defined policy. These exceptions may include HTTP(S)-based tools used for the administration of the local system, services, or attached devices. Examples of possible exceptions are HP’s System Management Homepage (SMH), the CUPS administrative interface, and Sun's StorageTek Common Array Manager (CAM) when these services are running on the local system.
V-4384
low
The version of the SMTP service can be used by attackers to plan an attack based on vulnerabilities present in the specific version.
V-4385
medium
The .forward file allows users to automatically forward mail to another system. Use of .forward files could allow the unauthorized forwarding of mail and could potentially create mail loops which could degrade system performance.
V-4387
high
If an anonymous FTP account has been configured to use a functional shell, attackers could gain access to the shell if the account is compromised.
V-4392
medium
Installing extraneous software on a system designated as a dedicated Network Management System (NMS) server poses a security threat to the system and the network. Should an attacker gain access to the NMS through unauthorized software, the entire network may be susceptible to malicious activity.
V-4393
medium
If the /etc/syslog.conf file is not owned by root, unauthorized users could be allowed to view, edit, or delete important system messages handled by the syslog facility.
V-4394
medium
If the group owner of /etc/syslog.conf is not root, bin, or sys, unauthorized users could be permitted to view, edit, or delete important system messages handled by the syslog facility.
V-4395
medium
If a remote log host is in use and it has not been justified and documented with the IAO, sensitive information could be obtained by unauthorized users without the SA's knowledge. A remote log host is any host to which the system is sending syslog messages over a network.
V-4397
medium
If a system has no default gateway defined, the system is at increased risk of man-in-the-middle, monitoring, and Denial of Service attacks.
V-4398
medium
Installing extraneous software on a system designated as a dedicated router poses a security threat to the system and the network. Should an attacker gain access to the router through the unauthorized software, the entire network is susceptible to malicious activity.
V-4399
high
Implementing NIS or NIS+ under UDP may make the system more susceptible to a Denial of Service attack and does not provide the same quality of service as TCP.
V-4427
medium
If these files are not properly configured, they could allow malicious access by unknown malicious users from untrusted hosts who could compromise the system.
V-4428
medium
If these files are accessible by users other than root or the owner, they could be used by a malicious user to set up a system compromise.
V-4430
medium
Cron daemon control files restrict the scheduling of automated tasks and must be protected.
V-4687
high
The rshd process provides a typically unencrypted, host-authenticated remote access service. SSH should be used in place of this service.
V-4688
high
The rexecd process provides a typically unencrypted, host-authenticated remote access service. SSH should be used in place of this service.
V-4689
high
The SMTP service version on the system must be current to avoid exposing vulnerabilities present in unpatched versions.
V-4690
high
Debug mode is a feature present in older versions of Sendmail which, if not disabled, may allow an attacker to gain access to a system through the Sendmail service.
V-4691
high
A common configuration for older Mail Transfer Agents (MTAs) includes an alias for the decode user. All mail sent to this user is sent to the uudecode program, which automatically converts and stores files. By sending mail to decode or uudecode aliases present on some systems, a remote attacker may be able to create or overwrite files on the remote host. This could possibly be used to gain remote access.
V-4692
low
The SMTP EXPN function allows an attacker to determine if an account exists on a system, providing significant assistance to a brute force attack on user accounts. EXPN may also provide additional information concerning users on the system, such as the full names of account owners.
V-4693
low
The VRFY (Verify) command allows an attacker to determine if an account exists on a system, providing significant assistance to a brute force attack on user accounts. VRFY may provide additional information about users on the system, such as the full names of account owners.
V-4694
low
Very old installations of the Sendmail mailing system contained a feature whereby a remote user connecting to the SMTP port can enter the WIZ command and be given an interactive shell with root privileges.
V-4695
high
TFTP is a file transfer protocol often used by embedded systems to obtain configuration data or software. The service is unencrypted and does not require authentication of requests. Data available using this service may be subject to unauthorized access or interception.
V-4696
medium
The UUCP utility is designed to assist in transferring files, executing remote commands, and sending e-mail between UNIX systems over phone lines and direct connections between systems. The UUCP utility is a primitive and arcane system with many security issues. There are alternate data transfer utilities/products that can be configured to more securely transfer data by providing for authentication as well as encryption.
V-4697
high
Open X displays allow an attacker to capture keystrokes and to execute commands remotely. Many users have their X Server set to xhost +, permitting access to the X Server by anyone, from anywhere.
V-4701
low
The finger service provides information about the system's users to network clients. This information could expose information that could be used in subsequent attacks.
V-4702
medium
Anonymous FTP is a public data service which is only permitted in a server capacity when located on the DMZ network.
V-72771
medium
The use of wireless networking can introduce many different attack vectors into the organization’s network. Common attack vectors such as malicious association and ad hoc networks will allow an attacker to spoof a wireless access point (AP), allowing validated systems to connect to the malicious AP and enabling the attacker to monitor and record network traffic. These malicious APs can also serve to create a man-in-the-middle attack or be used to create a denial of service to valid network resources.
V-756
medium
If the system does not require a valid root password before it boots into single-user or maintenance mode, anyone who invokes single-user or maintenance mode is granted privileged access to all files on the system.
V-760
medium
Shared accounts (accounts where two or more people log in with the same user identification) do not provide identification and authentication. There is no way to provide for non-repudiation or individual accountability.
V-761
medium
A unique user name is the first part of the identification and authentication process. If user names are not unique, there can be no accountability on the system for auditing purposes. Multiple accounts sharing the same name could result in the Denial of Service to one or both of the accounts or unauthorized access to files or privileges.
V-762
medium
Accounts that share a UID have full access to each others' files. This has the same effect as sharing a login. There is no way to assure identification, authentication, and accountability because the system sees them as the same user. If the duplicate UID is 0, this gives potential intruders another privileged account to attack.
V-763
medium
Failure to display the login banner prior to a logon attempt will negate legal proceedings resulting from unauthorized access to system resources.
V-765
medium
Monitoring and recording successful and unsuccessful logins assists in tracking unauthorized access to the system. Without this logging, the ability to track unauthorized activity to specific user accounts may be diminished.
V-766
medium
Disabling accounts after a limited number of unsuccessful login attempts improves protection against password guessing attacks.
V-768
medium
Enforcing a delay between successive failed login attempts increases protection against automated password guessing attacks.
V-769
medium
If an application is providing a continuous display and is running with root privileges, unauthorized users could interrupt the process and gain root access to the system.
V-770
high
If an account is configured for password authentication but does not have an assigned password, it may be possible to log into the account without authentication. If the root user is configured without a password, the entire system may be compromised. For user accounts not using password authentication, the account must be configured with a password lock value instead of a blank or null value.
V-773
medium
If an account has an UID of 0, it has root authority. Multiple accounts with an UID of 0 afford more opportunity for potential intruders to guess a password for a privileged account.
V-774
low
Changing the root home directory to something other than / and assigning it a 0700 protection makes it more difficult for intruders to manipulate the system by reading the files that root places in its default directory. It also gives root the same discretionary access control for root's home directory as for the other plain user home directories.
V-775
medium
Permissions greater than 0700 could allow unauthorized users access to the root home directory.
V-776
medium
The executable search path (typically the PATH environment variable) contains a list of directories for the shell to search to find executables. If this path includes the current working directory or other relative paths, executables in these directories may be executed instead of system commands. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, two consecutive colons, or a single period, this is interpreted as the current working directory. Entries starting with a slash (/) are absolute paths.
V-777
medium
If the root search path contains a world-writable directory, malicious software could be placed in the path by intruders and/or malicious users and inadvertently run by root with all of root's privileges.
V-778
medium
Limiting the root account direct logins to only system consoles protects the root account from direct unauthorized access from a non-console device.
V-780
medium
Reserved GIDs are typically used by system software packages. If non-system groups have GIDs in this range, they may conflict with system software, possibly leading to the group having permissions to modify system files.
V-781
low
If a user is assigned the GID of a group that does not exist on the system, and a group with that GID is subsequently created, the user may have unintended rights to the group.
V-782
medium
Without a host-based intrusion detection tool, there is no system-level defense when an intruder gains access to a system or network. Additionally, a host-based intrusion detection tool can provide methods to immediately lock out detected intrusion attempts.
V-783
medium
Timely patching is critical for maintaining the operational availability, confidentiality, and integrity of Information Technology (IT) systems. However, failure to keep operating system and application software patched is a common mistake made by IT professionals. New patches are released daily, and it is often difficult for even experienced system administrators to keep abreast of all the new patches. When new weaknesses in an operating system exist, patches are usually made available by the vendor to resolve the problems. If the most recent security patches and updates are not installed, unauthorized users may take advantage of weaknesses present in the unpatched software. The lack of prompt attention to patching could result in a system compromise.
V-784
medium
Discretionary access control is undermined if users, other than a file owner, have greater access permissions to system files and directories than the owner.
V-785
medium
Unowned files and directories may be unintentionally inherited if a user is assigned the same UID as the UID of the unowned files.
V-786
medium
Restricting permission on daemons will protect them from unauthorized modification and possible system compromise.
V-787
medium
If the system log files are not protected, unauthorized users could change the logged data, eliminating its forensic value.
V-788
medium
If the skeleton files are not protected, unauthorized personnel could change user startup parameters and possibly jeopardize user files.

V-789
medium
NIS/NIS+/yp files are part of the system's identification and authentication processes and are, therefore, critical to system security. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.
V-790
medium
NIS/NIS+/yp files are part of the system's identification and authentication processes and are, therefore, critical to system security. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.
V-791
medium
NIS/NIS+/yp files are part of the system's identification and authentication processes and are, therefore, critical to system security. Unauthorized modification of these files could compromise these processes and the system.
V-792
low
If manual pages are compromised, misleading information could be inserted, causing actions that may compromise the system.
V-793
medium
Unauthorized access could destroy the integrity of the library files.
V-794
medium
Restricting permissions will protect system command files from unauthorized modification. System command files include files present in directories used by the operating system for storing default system executables and files present in directories included in the system's default executable search paths.
V-795
medium
Restricting permissions will protect the files from unauthorized modification.
V-796
medium
Restricting permissions will protect the files from unauthorized modification.
V-797
medium
The /etc/security/passwd file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.
V-798
medium
If the password file is writable by a group owner or the world, the risk of password file compromise is increased. The password file contains the list of accounts on the system and associated information.
V-800
medium
The /etc/security/passwd file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification. The file also contains password hashes which must not be accessible to users other than root.
V-801
medium
All files with the setuid bit set will allow anyone running these files to be temporarily assigned the UID of the file. While many system files depend on these attributes for proper operation, security problems can result if setuid is assigned to programs that allow reading and writing of files, or shell escapes. Only default vendor-supplied executables should have the setuid bit set.
V-802
medium
All files with the setgid bit set will allow anyone running these files to be temporarily assigned the GID of the file. While many system files depend on these attributes for proper operation, security problems can result if setgid is assigned to programs that allow reading and writing of files, or shell escapes.
V-803
medium
Files with the setuid bit set will allow anyone running these files to be temporarily assigned the UID of the file. While many system files depend on these attributes for proper operation, security problems can result if setuid is assigned to programs that allow reading and writing of files, or shell escapes.
V-804
medium
Files with the setgid bit set will allow anyone running these files to be temporarily assigned the group id of the file. While many system files depend on these attributes for proper operation, security problems can result if setgid is assigned to programs that allow reading and writing of files, or shell escapes.
V-805
medium
The nosuid mount option causes the system to not execute setuid files with owner privileges. This option must be used for mounting any file system not containing approved setuid files. Executing setuid files from untrusted file systems, or file systems not containing approved setuid files, increases the opportunity for unprivileged users to attain unauthorized administrative access.
V-806
low
Failing to set the sticky bit on the public directories allows unauthorized users to delete files in the directory structure.

The only authorized public directories are those temporary directories supplied with the system or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system and by users for temporary file storage (e.g., /tmp) and for directories requiring global read/write access.
V-807
medium
If a public directory has the sticky bit set and is not owned by a privileged UID, unauthorized users may be able to modify files created by others.

The only authorized public directories are those temporary directories supplied with the system or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system and by users for temporary file storage (e.g., /tmp) and for directories requiring global read/write access.
V-808
medium
The umask controls the default access mode assigned to newly created files. An umask of 077 limits new files to mode 700 or less permissive. Although umask can be represented as a 4-digit number, the first digit representing special access modes is typically ignored or required to be 0. This requirement applies to the globally configured system defaults and the user defaults for each account on the system.
V-810
medium
Vendor accounts and software may contain backdoors allowing unauthorized access to the system. These backdoors are common knowledge and present a threat to system security if the account is not disabled.
V-811
medium
Without auditing, individual system accesses cannot be tracked and malicious activity cannot be detected and traced back to an individual account.
V-812
medium
Failure to give ownership of system audit log files to root provides the designated owner and unauthorized users with the potential to access sensitive information.
V-813
medium
If a user can write to the audit logs, audit trails can be modified or destroyed and system intrusion may not be detected. System audit logs are those files generated from the audit system and do not include activity, error, or other log files created by application software.
V-814
medium
If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.
V-815
medium
If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.
V-816
medium
If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.
V-818
medium
If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.
V-819
medium
If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.
V-821
medium
Failure to give ownership of sensitive files or utilities to root provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.
V-822
medium
The Internet service daemon configuration files must be protected as malicious modification could cause Denial of Service or increase the attack surface of the system.
V-823
medium
Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.
V-824
medium
The services file is critical to the proper operation of network services and must be protected from unauthorized modification. Unauthorized modification could result in the failure of network services.
V-825
low
If the mesg -n or mesg n command is not placed into the system profile, messaging can be used to cause a Denial of Service attack.
V-827
medium
Having the "+" character in the hosts.lpd (or equivalent) file allows all hosts to use local system print resources.
V-828
medium
Failure to give ownership of the hosts.lpd file to root, bin, sys, or lp provides the designated owner, and possible unauthorized users, with the potential to modify the hosts.lpd file. Unauthorized modifications could disrupt access to local printers from authorized remote hosts or permit unauthorized remote access to local printers.
V-829
medium
Excessive permissions on the hosts.lpd (or equivalent) file may permit unauthorized modification. Unauthorized modifications could disrupt access to local printers from authorized remote hosts or permit unauthorized remote access to local printers.
V-831
medium
If the alias file is not owned by root, an unauthorized user may modify the file to add aliases to run malicious code or redirect email.
V-832
medium
Excessive permissions on the aliases file may permit unauthorized modification. If the alias file is modified by an unauthorized user, they may modify the file to run malicious code or redirect email.
V-833
high
If a file executed through a mail aliases file is not owned and writable only by root, it may be subject to unauthorized modification. Unauthorized modification of files executed through aliases may allow unauthorized users to attain root privileges.
V-834
medium
If a file executed through a mail alias file has permissions greater than 0755, it can be modified by an unauthorized user and may contain malicious code or instructions possibly compromising the system.
V-835
low
If Sendmail is not configured to log at level 9, system logs may not contain the information necessary for tracking unauthorized use of the Sendmail service.
V-836
medium
If informational and more severe SMTP service messages are not logged, malicious activity on the system may go unnoticed.
V-837
medium
If the SMTP service log file is not owned by root, then unauthorized personnel may modify or delete the file to hide a system compromise.
V-838
medium
If the SMTP service log file is more permissive than 0644, unauthorized users may be allowed to change the log file.
V-840
medium
The ftpusers file contains a list of accounts not allowed to use FTP to transfer files. If this file does not exist, then unauthorized accounts can utilize FTP.
V-841
medium
The ftpusers file contains a list of accounts not allowed to use FTP to transfer files. If the file does not contain the names of all accounts not authorized to use FTP, then unauthorized use of FTP may take place.
V-842
medium
If the file ftpusers is not owned by root, an unauthorized user may modify the file to allow unauthorized accounts to use FTP.
V-843
medium
Excessive permissions on the ftpusers file could permit unauthorized modification. Unauthorized modification could result in Denial of Service to authorized FTP users or permit unauthorized users to access the FTP service.
V-845
low
The -l option allows logging of connections. This extra logging makes it possible to easily track which files are being transferred onto or from a system. If they are not configured, the only option for tracking is the audit files. The audit files are much harder to read. If auditing is not properly configured, then there would be no record at all of the file transfer transactions.
V-846
medium
Due to the numerous vulnerabilities inherent in anonymous FTP, it is recommended that it not be used. If anonymous FTP must be used on a system, the requirement must be authorized and approved in the system accreditation package.
V-847
high
Secure mode limits TFTP requests to a specific directory. If TFTP is not running in secure mode, it may be able to write to any file or directory and may seriously impair system integrity, confidentiality, and availability.
V-848
high
If TFTP runs with the setuid or setgid bit set, it may be able to write to any file or directory and may seriously impair system integrity, confidentiality, and availability.
V-849
medium
If TFTP has a valid shell, it increases the likelihood of someone logging to the TFTP account and compromising the system.
V-867
medium
Due to numerous security vulnerabilities existing within NIS, it must not be used. Possible alternative directory services are NIS+ and LDAP.
V-899
low
If users do not have a valid home directory, there is no place for the storage and control of files they own.
V-900
low
If a user has a home directory defined that does not exist, the user may be given the / directory, by default, as the current working directory upon logon. This could create a Denial of Service because the user would not be able to perform useful tasks in this location.
V-901
medium
Excessive permissions on home directories allow unauthorized access to user's files.
V-902
medium
If users do not own their home directories, unauthorized users could access user files.
V-903
medium
If the GID of the home directory is not the same as the GID of the user, this would allow unauthorized access to files.
V-905
medium
Local initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon.
V-906
medium
If the startup files are writable by other users, they could modify the startup files to insert malicious commands into the startup files.
V-907
medium
The executable search path (typically the PATH environment variable) contains a list of directories for the shell to search to find executables. If this path includes the current working directory or other relative paths, executables in these directories may be executed instead of system commands. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, two consecutive colons, or a single period, this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths.
V-910
high
World-writable files could be modified accidentally or maliciously to compromise system integrity.
V-913
medium
Unencrypted passwords for remote FTP servers may be stored in .netrc files. Policy requires passwords be encrypted in storage and not used in access scripts.
V-914
low
If users do not own the files in their directories, unauthorized users may be able to access them. Additionally, if files are not owned by the user, this could be an indication of system compromise.
V-915
low
Excessive permissions allow unauthorized access to user's files.
V-916
medium
The shells file (or equivalent) lists approved default shells. It helps provide layered defense to the security approach by ensuring users cannot change their default shell to an unauthorized shell that may not be secure.
V-917
medium
The shells file lists approved default shells. It helps provide layered defense to the security approach by ensuring users cannot change their default shell to an unauthorized shell that may not be secure.
V-918
medium
On some systems, accounts with disabled passwords still allow access using rcp, remsh, or rlogin through equivalent remote hosts. All that is required is the remote host name and the user name match an entry in a hosts.equiv file and have a .rhosts file in the user directory. Using a shell called /bin/false or /dev/null (or an equivalent) will add a layered defense.

Non-interactive accounts on the system, such as application accounts, may be documented exceptions.
V-921
medium
If shell files are owned by users other than root or bin, they could be modified by intruders or malicious users to perform unauthorized actions.
V-922
high
Shells with world/group write permissions give the ability to maliciously modify the shell to obtain unauthorized access.
V-923
low
If an unauthorized device is allowed to exist on the system, there is the possibility the system may perform unauthorized operations.
V-924
medium
System device files in writable directories could be modified, removed, or used by an unprivileged user to control system hardware.
V-925
medium
System backups could be accidentally or maliciously overwritten and destroy the ability to recover the system if a compromise should occur. Unauthorized users could also copy system files.
V-926
medium
If the NIS+ server is not operating in, at least, security level 2, there is no encryption and the system could be penetrated by intruders and/or malicious users.
V-928
medium
Failure to give ownership of the NFS export configuration file to root provides the designated owner and possible unauthorized users with the potential to change system configuration which could weaken the system's security posture.
V-929
low
Excessive permissions on the NFS export configuration file could allow unauthorized modification of the file, which could result in Denial of Service to authorized NFS exports and the creation of additional unauthorized exports.
V-931
medium
Failure to give ownership of sensitive files or directories to root provides the designated owner and possible unauthorized users with the potential to access sensitive information or change system configuration which could weaken the system's security posture.
V-932
medium
When an NFS server is configured to deny remote root access, a selected UID and GID are used to handle requests from the remote root user. The UID and GID should be chosen from the system to provide the appropriate level of non-privileged access.
V-933
medium
The NFS access option limits user access to the specified level. This assists in protecting exported file systems. If access is not restricted, unauthorized hosts may be able to access the system's NFS exports.
V-936
medium
Enabling the nosuid mount option prevents the system from granting owner or group-owner privileges to programs with the suid or sgid bit set. If the system does not restrict this access, users with unprivileged access to the local system may be able to acquire privileged access by executing suid or sgid files located on the mounted NFS file system.
V-940
medium
Access control programs (such as TCP_WRAPPERS) provide the ability to enhance system security posture.
V-969
medium
The AIX Trusted Computing Base (TCB) software provides protection from the unauthorized modification of core system files.
V-974
medium
The cron facility allows users to execute recurring jobs on a regular and unattended basis. The cron.allow file designates accounts allowed to enter and execute jobs using the cron facility. If neither cron.allow nor cron.deny exists, then any account may use the cron facility. This may open the facility up for abuse by system intruders and malicious users.
V-975
medium
A cron.allow file that is readable and/or writable by other than root could allow potential intruders and malicious users to use the file contents to help discern information, such as who is allowed to execute cron programs, which could be harmful to overall system and network security.
V-976
medium
If cron executes group-writable or world-writable programs, there is a possibility that unauthorized users could manipulate the programs with malicious intent. This could compromise system and network security.
V-977
medium
If cron programs are located in or subordinate to world-writable directories, they become vulnerable to removal and replacement by malicious users or system intruders.
V-978
medium
To protect the integrity of scheduled system jobs and prevent malicious modification to these jobs, crontab files must be secured.
V-979
medium
To protect the integrity of scheduled system jobs and to prevent malicious modification to these jobs, crontab files must be secured.
V-980
medium
Incorrect ownership of the cron or crontab directories could permit unauthorized users the ability to alter cron jobs and run automated jobs as privileged users. Failure to give ownership of cron or crontab directories to root or to bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.
V-981
medium
To protect the integrity of scheduled system jobs and to prevent malicious modification to these jobs, crontab files must be secured. Failure to give group ownership of cron or crontab directories to a system group provides the designated group and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture.
V-982
medium
Cron logging can be used to trace the successful or unsuccessful execution of cron jobs. It can also be used to spot intrusions into the use of the cron facility by unauthorized and malicious users.
V-983
medium
Cron logs contain reports of scheduled system activities and must be protected from unauthorized access or manipulation.
V-984
medium
The at facility selectively allows users to execute jobs at deferred times. It is usually used for one-time jobs. The at.allow file selectively allows access to the at facility. If there is no at.allow file, there is no ready documentation of who is allowed to submit at jobs.
V-985
medium
On some systems, if there is no at.allow file and there is an empty at.deny file, then the system assumes everyone has permission to use the at facility. This could create an insecure setting in the case of malicious users or system intruders.
V-986
medium
Default accounts, such as bin, sys, adm, uucp, daemon, and others, should never have access to the at facility. This would create a possible vulnerability open to intruders or malicious users.
V-987
medium
Permissions more permissive than 0600 (read, write and execute for the owner) may allow unauthorized or malicious access to the at.allow and/or at.deny files.
V-988
medium
If the at facility executes world-writable or group-writable programs, it is possible for the programs to be accidentally or maliciously changed or replaced without the owner's intent or knowledge. This would cause a system security breach.
V-989
medium
If "at" programs are located in, or subordinate, to world-writable directories, they become vulnerable to removal and replacement by malicious users or system intruders.
V-993
high
Whether active or not, default SNMP passwords, users, and passphrases must be changed to maintain security. If the service is running with the default authenticators, then anyone can gather data about the system and the network and use the information to potentially compromise the integrity of the system or network(s).
V-994
medium
The snmpd.conf file contains authenticators and must be protected from unauthorized access and modification.
V-995
medium
The ability to read the MIB file could impart special knowledge to an intruder or malicious user about the ability to extract compromising information about the system or network.
506 total