SLES 12 Security Technical Implementation Guide (V2 R5)

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ArchivedPublished Wed Oct 27 2021

Objective ID

Severity

Discussion

V-217101

high

A SUSE 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-217102

medium

Timely patching is critical for maintaining the operational availability, confidentiality, and integrity of information technology (IT) systems. However, failure to keep SUSE operating system and application software patched is a common mistake made by IT professionals. New patches are released frequently, and it is often difficult for even experienced System Administrators (SAs) to keep abreast of all the new patches. When new weaknesses in a SUSE 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 in the unpatched software. The lack of prompt attention to patching could result in a system compromise.

V-217103

medium

Display of a standardized and approved use notification before granting access to the SUSE operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.

The banner must be acknowledged by the user prior to allowing the user access to the SUSE operating system. This provides assurance that the user has seen the message and accepted the conditions for access. If the consent banner is not acknowledged by the user, DoD will not be in compliance with system use notifications required by law.

System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist.

The banner must be formatted in accordance with applicable DoD policy. Use the following verbiage for the SUSE operating system:

"You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only.

By using this IS (which includes any device attached to this IS), you consent to the following conditions:

-The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations.

-At any time, the USG may inspect and seize data stored on this IS.

-Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose.

-This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy.

-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details."

Satisfies: SRG-OS-000023-GPOS-00006, SRG-OS-000024-GPOS-00007

V-217104

medium

Display of a standardized and approved use notification before granting access to the SUSE operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.

The banner must be acknowledged by the user prior to allowing the user access to the SUSE operating system. This provides assurance that the user has seen the message and accepted the conditions for access. If the consent banner is not acknowledged by the user, DoD will not be in compliance with system use notifications required by law.

System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist.

The banner must be formatted in accordance with applicable DoD policy. Use the following verbiage for SUSE operating system:

"You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only.

By using this IS (which includes any device attached to this IS), you consent to the following conditions:

-The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations.

-At any time, the USG may inspect and seize data stored on this IS.

-Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose.

-This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy.

-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details."

V-217105

medium

Display of a standardized and approved use notification before granting access to the SUSE operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.

The banner must be acknowledged by the user prior to allowing the user access to the SUSE operating system. This provides assurance that the user has seen the message and accepted the conditions for access. If the consent banner is not acknowledged by the user, DoD will not be in compliance with system use notifications required by law.

System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist.

The banner must be formatted in accordance with applicable DoD policy. Use the following verbiage for SUSE operating system:

"You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only.

By using this IS (which includes any device attached to this IS), you consent to the following conditions:

-The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations.

-At any time, the USG may inspect and seize data stored on this IS.

-Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose.

-This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy.

-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details."

V-217106

medium

Display of a standardized and approved use notification before granting access to the SUSE operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.

The banner must be acknowledged by the user prior to allowing the user access to the SUSE operating system. This provides assurance that the user has seen the message and accepted the conditions for access. If the consent banner is not acknowledged by the user, DoD will not be in compliance with system use notifications required by law.

System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist.

The banner must be formatted in accordance with applicable DoD policy. Use the following verbiage for SUSE operating system:

"You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only.

By using this IS (which includes any device attached to this IS), you consent to the following conditions:

-The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations.

-At any time, the USG may inspect and seize data stored on this IS.

-Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose.

-This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy.

-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details."

V-217107

medium

A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to log out because of the temporary nature of the absence.

The session lock is implemented at the point where session activity can be determined.

Regardless of where the session lock is determined and implemented, once invoked, the session lock must remain in place until the user reauthenticates. No other activity aside from reauthentication must unlock the system.

Satisfies: SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011

V-217108

low

V-217109

medium

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not log out because of the temporary nature of the absence.

Rather than relying on the users to manually lock their SUSE operating system session prior to vacating the vicinity, the SUSE operating system needs to be able to identify when a user's session has idled and take action to initiate the session lock.

The session lock is implemented at the point where session activity can be determined and/or controlled.

V-217110

medium

V-217111

low

A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not log out because of the temporary nature of the absence.

The session lock is implemented at the point where session activity can be determined. The SUSE operating system session lock event must include an obfuscation of the display screen to prevent other users from reading what was previously displayed.

Publicly viewable images can include static or dynamic images, such as patterns used with screen savers, photographic images, solid colors, a clock, a battery life indicator, or a blank screen, with the additional caveat that none of the images conveys sensitive information.

V-217112

high

Without reauthentication, users may access resources or perform tasks for which they do not have authorization.

When SUSE operating system provide the capability to change user authenticators, change security roles, or escalate a functional capability, it is critical the user reauthenticate.

Satisfies: SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158

V-217113

low

SUSE operating system management includes the ability to control the number of users and user sessions that utilize a SUSE operating system. Limiting the number of allowed users and sessions per user is helpful in reducing the risks related to Denial-of-Service (DoS) attacks.

This requirement addresses concurrent sessions for information system accounts and does not address concurrent sessions by single users via multiple system accounts. The maximum number of concurrent sessions should be defined based on mission needs and the operational environment for each system.

V-217114

medium

By limiting the number of failed access attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account.

The pam_tally2.so module maintains a count of attempted accesses. This includes user name entry into a logon field as well as password entry. With counting access attempts, it is possible to lock an account without presenting a password into the password field. This should be taken into consideration as it poses as an avenue for denial of service.

V-217116

medium

Limiting the number of logon attempts over a certain time interval reduces the chances that an unauthorized user may gain access to an account.

V-217117

medium

Use of a complex password helps increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.

Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised.

V-217118

medium

V-217119

medium

V-217120

medium

Use of a complex password helps increase the time and resources required to compromise the password. Password complexity or strength is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.

Password complexity is one factor in determining how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised.

Special characters are not alphanumeric. Examples include: ~ ! @ # $ % ^ *.

V-217121

medium

If the SUSE operating system allows the user to consecutively reuse extensive portions of passwords, this increases the chances of password compromise by increasing the window of opportunity for attempts at guessing and brute-force attacks.

The number of changed characters refers to the number of changes required with respect to the total number of positions in the current password. In other words, characters may be the same within the two passwords; however, the positions of the like characters must be different.

V-217122

medium

Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied on to provide confidentiality or integrity, and DoD data may be compromised.

SUSE operating systems using encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules.

FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules use authentication that meets DoD requirements. This allows for Security Levels 1, 2, 3, or 4 for use on a general purpose computing system.

V-217123

medium

The system must use a strong hashing algorithm to store the password. The system must use a sufficient number of hashing rounds to ensure the required level of entropy.

Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised.

Satisfies: SRG-OS-000073-GPOS-00041, SRG-OS-000120-GPOS-00061

V-217124

medium

Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised.

Satisfies: SRG-OS-000120-GPOS-00061

V-217125

medium

V-217126

medium

V-217127

medium

The shorter the password, the lower the number of possible combinations that need to be tested before the password is compromised.

Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password length is one factor of several that helps determine strength and how long it takes to crack a password. Use of more characters in a password helps exponentially increase the time and/or resources required to compromise the password.

V-217128

medium

Enforcing a minimum password lifetime helps prevent repeated password changes to defeat the password reuse or history enforcement requirement. If users are allowed to immediately and continually change their password, the password could be repeatedly changed in a short period of time to defeat the organization's policy regarding password reuse.

V-217129

medium

V-217130

medium

Any password, no matter how complex, can eventually be cracked. Therefore, passwords need to be changed periodically. If the SUSE operating system does not limit the lifetime of passwords and force users to change their passwords, there is the risk that the SUSE operating system passwords could be compromised.

V-217131

medium

V-217132

medium

Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. If the information system or application allows the user to consecutively reuse their password when that password has exceeded its defined lifetime, the end result is a password that is not changed as per policy requirements.

V-217133

medium

V-217134

medium

If the SUSE operating system allows the user to select passwords based on dictionary words, this increases the chances of password compromise by increasing the opportunity for successful guesses and brute-force attacks.

V-217135

medium

Emergency accounts are privileged accounts that are established in response to crisis situations where the need for rapid account activation is required. Therefore, emergency account activation may bypass normal account authorization processes. If these accounts are automatically disabled, system maintenance during emergencies may not be possible, thus adversely affecting system availability.

Emergency accounts are different from infrequently used accounts (i.e., local logon accounts used by the organization's system administrators when network or normal logon/access is not available). Infrequently used accounts are not subject to automatic termination dates. Emergency accounts are accounts created in response to crisis situations, usually for use by maintenance personnel. The automatic expiration or disabling time period may be extended as needed until the crisis is resolved; however, it must not be extended indefinitely. A permanent account should be established for privileged users who need long-term maintenance accounts.

To address access requirements the SUSE operating system can be integrated with enterprise-level authentication/access mechanisms that meet or exceed access control policy requirements.

V-217136

medium

Inactive identifiers pose a risk to systems and applications because attackers may exploit an inactive identifier and potentially obtain undetected access to the system. Owners of inactive accounts will not notice if unauthorized access to their user account has been obtained.

The SUSE operating system needs to track periods of inactivity and disable application identifiers after 35 days of inactivity.

V-217137

medium

If temporary user accounts remain active when no longer needed or for an excessive period, these accounts may be used to gain unauthorized access. To mitigate this risk, automated termination of all temporary accounts must be set upon account creation.

Temporary accounts are established as part of normal account activation procedures when there is a need for short-term accounts without the demand for immediacy in account activation.

If temporary accounts are used, the SUSE operating system must be configured to automatically terminate these types of accounts after a DoD-defined time period of 72 hours.

To address access requirements, many SUSE operating systems may be integrated with enterprise-level authentication/access mechanisms that meet or exceed access control policy requirements.

V-217138

medium

Limiting the number of logon attempts over a certain time interval reduces the chances that an unauthorized user may gain access to an account.

V-217139

high

Failure to restrict system access to authenticated users negatively impacts SUSE operating system security.

V-217140

low

Providing users with feedback on when account accesses last occurred facilitates user recognition and reporting of unauthorized account use.

V-217141

high

The .shosts files are used to configure host-based authentication for individual users or the system via SSH. Host-based authentication is not sufficient for preventing unauthorized access to the system, as it does not require interactive identification and authentication of a connection request, or for the use of two-factor authentication.

V-217142

high

The shosts.equiv files are used to configure host-based authentication for the system via SSH. Host-based authentication is not sufficient for preventing unauthorized access to the system, as it does not require interactive identification and authentication of a connection request, or for the use of two-factor authentication.

V-217143

medium

Use of weak or untested encryption algorithms undermines the purposes of using encryption to protect data. The SUSE operating system must implement cryptographic modules adhering to the higher standards approved by the federal government since this provides assurance they have been tested and validated.

Satisfies: SRG-OS-000396-GPOS-00176, SRG-OS-000478-GPOS-00223

V-217144

medium

To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement.

Access control policies include identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.

V-217145

medium

If the system allows a user to boot into single-user or maintenance mode without authentication, any user that invokes single-user or maintenance mode is granted privileged access to all system information.

If the system is running in EFI mode, SLES 12 by default will use GRUB 2 EFI as the boot loader.

V-217146

medium

SUSE operating systems handling data requiring "data at rest" protections must employ cryptographic mechanisms to prevent unauthorized disclosure and modification of the information at rest.

Selection of a cryptographic mechanism is based on the need to protect the integrity of organizational information. The strength of the mechanism is commensurate with the security category and/or classification of the information. Organizations have the flexibility to either encrypt all information on storage devices (i.e., full disk encryption) or encrypt specific data structures (e.g., files, records, or fields).

Satisfies: SRG-OS-000185-GPOS-00079, SRG-OS-000404-GPOS-00183, SRG-OS-000405-GPOS-00184

V-217147

medium

Preventing unauthorized information transfers mitigates the risk of information, including encrypted representations of information, produced by the actions of prior users/roles (or the actions of processes acting on behalf of prior users/roles) from being available to any current users/roles (or current processes) that obtain access to shared system resources (e.g., registers, main memory, and hard disks) after those resources have been released back to information systems. The control of information in shared resources is also commonly referred to as object reuse and residual information protection.

This requirement generally applies to the design of an information technology product, but it can also apply to the configuration of particular information system components that are, or use, such products. This can be verified by acceptance/validation processes in DoD or other government agencies.

There may be shared resources with configurable protections (e.g., files in storage) that may be assessed on specific information system components.

V-217148

medium

Unauthorized changes to the baseline configuration could make the system vulnerable to various attacks or allow unauthorized access to the SUSE operating system. Changes to SUSE operating system configurations can have unintended side effects, some of which may be relevant to security.

Detecting such changes and providing an automated response can help avoid unintended, negative consequences that could ultimately affect the security state of the SUSE operating system. The SUSE operating system's Information Management Officer (IMO)/Information System Security Officer (ISSO) and System Administrator (SAs) must be notified via email and/or monitoring system trap when there is an unauthorized modification of a configuration item.

V-217149

medium

If anomalies are not acted on, security functions may fail to secure the system.

Security function is defined as the hardware, software, and/or firmware of the information system responsible for enforcing the system security policy and supporting the isolation of code and data on which the protection is based. Security functionality includes, but is not limited to, establishing system accounts, configuring access authorizations (i.e., permissions, privileges), setting events to be audited, and setting intrusion detection parameters.

Notifications provided by information systems include messages to local computer consoles and/or hardware indications, such as lights.

This capability must take into account operational requirements for availability for selecting an appropriate response. The organization may choose to shut down or restart the information system upon security function anomaly detection.

V-217150

low

ACLs can provide permissions beyond those permitted through the file mode and must be verified by file integrity tools.

V-217151

low

Extended attributes in file systems are used to contain arbitrary data and file metadata with security implications.

V-217152

medium

Protecting the integrity of the tools used for auditing purposes is a critical step toward ensuring the integrity of audit information. Audit information includes all information (e.g., audit records, audit settings, and audit reports) needed to successfully audit information system activity.

Audit tools include but are not limited to vendor-provided and open-source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators.

It is not uncommon for attackers to replace the audit tools or inject code into the existing tools to provide the capability to hide or erase system activity from the audit logs.

To address this risk, audit tools must be cryptographically signed to provide the capability to identify when the audit tools have been modified, manipulated, or replaced. An example is a checksum hash of the file or files.

V-217153

medium

Changes to any software components can have significant effects on the overall security of the SUSE operating system. This requirement ensures the software has not been tampered with and has been provided by a trusted vendor.

Accordingly, patches, service packs, device drivers, or SUSE operating system components must be signed with a certificate recognized and approved by the organization.

Verifying the authenticity of the software prior to installation validates the integrity of the patch or upgrade received from a vendor. This ensures the software has not been tampered with and that it has been provided by a trusted vendor. Self-signed certificates are disallowed by this requirement. The SUSE operating system should not have to verify the software again. This requirement does not mandate DoD certificates for this purpose; however, the certificate used to verify the software must be from an approved Certification Authority (CA).

V-217154

medium

Previous versions of software components that are not removed from the information system after updates have been installed may be exploited by adversaries. Some information technology products may remove older versions of software automatically from the information system.

V-217155

medium

Without identifying devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity.

Peripherals include but are not limited to such devices as flash drives, external storage, and printers.

V-217156

medium

Automatically mounting file systems permits easy introduction of unknown devices, thereby facilitating malicious activity.

Satisfies: SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227

V-217158

medium

Using a whitelist provides a configuration management method for allowing the execution of only authorized software. Using only authorized software decreases risk by limiting the number of potential vulnerabilities.

The organization must identify authorized software programs and permit execution of authorized software by adding each authorized program to the "pam_apparmor" exception policy. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting.

Verification of whitelisted software occurs prior to execution or at system startup.

Users' home directories/folders may contain information of a sensitive nature. Nonprivileged users should coordinate any sharing of information with a System Administrator (SA) through shared resources.

Apparmor can confine users to their home directory, not allowing them to make any changes outside of their own home directories. Confining users to their home directory will minimize the risk of sharing information.

Satisfies: SRG-OS-000312-GPOS-00122, SRG-OS-000312-GPOS-00123SRG-OS-000312-GPOS-00124, SRG-OS-000324-GPOS-00125, SRG-OS-000326-GPOS-00126, SRG-OS-000370-GPOS-00155, SRG-OS-000480-GPOS-00230

V-217159

high

V-217160

high

A locally logged-on user who presses Ctrl-Alt-Delete, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of a mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot. In the GNOME graphical environment, risk of unintentional reboot from the Ctrl-Alt-Delete sequence is reduced because the user will be prompted before any action is taken.

V-217161

medium

Setting the most restrictive default permissions ensures that when new accounts are created, they do not have unnecessary access.

V-217162

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-217163

medium

To assure accountability and prevent unauthenticated access, interactive users must be identified and authenticated to prevent potential misuse and compromise of the system.

Interactive users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Interactive users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following:

1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and

2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity.

Satisfies: SRG-OS-000104-GPOS-00051, SRG-OS-000121-GPOS-00062

V-217164

high

If an account other than root also has a User Identifier (UID) of "0", it has root authority, giving that account unrestricted access to the entire SUSE operating system. Multiple accounts with a UID of "0" afford an opportunity for potential intruders to guess a password for a privileged account.

V-217166

medium

If cached authentication information is out of date, the validity of the authentication information may be questionable.

V-217167

medium

If cached authentication information is out of date, the validity of the authentication information may be questionable.

V-217168

medium

Unowned files and directories may be unintentionally inherited if a user is assigned the same User Identifier (UID) as the UID of the unowned files.

V-217169

medium

Files without a valid group owner may be unintentionally inherited if a group is assigned the same Group Identifier (GID) as the GID of the files without a valid group owner.

V-217170

medium

If local interactive users are not assigned a valid home directory, there is no place for the storage and control of files they should own.

V-217171

medium

If local interactive users are not assigned a valid home directory, there is no place for the storage and control of files they should own.

V-217172

medium

If a local interactive user has a home directory defined that does not exist, the user may be given access to the / directory as the current working directory upon logon. This could create a Denial of Service because the user would not be able to access their logon configuration files, and it may give them visibility to system files they normally would not be able to access.

V-217173

medium

Excessive permissions on local interactive user home directories may allow unauthorized access to user files by other users.

V-217174

medium

If the Group Identifier (GID) of a local interactive user’s home directory is not the same as the primary GID of the user, this would allow unauthorized access to the user’s files, and users that share the same group may not be able to access files that they legitimately should.

V-217175

medium

Local initialization files are used to configure the user's shell environment upon logon. Malicious modification of these files could compromise accounts upon logon.

V-217176

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 (other than the user's home directory), 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 or two consecutive colons, this is interpreted as the current working directory. If deviations from the default system search path for the local interactive user are required, they must be documented with the Information System Security Officer (ISSO).

V-217177

medium

If user start-up files execute world-writable programs, especially in unprotected directories, they could be maliciously modified to destroy user files or otherwise compromise the system at the user level. If the system is compromised at the user level, it is easier to elevate privileges to eventually compromise the system at the root and network level.

V-217178

medium

The "nosuid" mount option causes the system to not execute setuid and setgid files with owner privileges. This option must be used for mounting any file system not containing approved setuid and setguid files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

V-217179

medium

The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

V-217180

medium

V-217181

medium

The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

V-217182

medium

If a world-writable directory has the sticky bit set and is not group-owned by a privileged Group Identifier (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-217183

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 partition.

V-217184

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-217185

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-217186

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-217188

medium

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the SUSE operating system or platform. Additionally, Personally Identifiable Information (PII) and operational information must not be revealed through error messages to unauthorized personnel or their designated representatives.

The structure and content of error messages must be carefully considered by the organization and development team. The extent to which the information system is able to identify and handle error conditions is guided by organizational policy and operational requirements.

V-217189

medium

"pam-config" is a command line utility that automatically generates a system PAM configuration as packages are installed, updated or removed from the system. "pam-config" removes configurations for PAM modules and parameters that it does not know about. It may render ineffective PAM configuration by the system administrator and thus impact system security.

V-217190

medium

Without establishing what type of events occurred, the source of events, where events occurred, and the outcome of events, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack.

Audit record content that may be necessary to satisfy this requirement includes, for example, time stamps, source and destination addresses, user/process identifiers, event descriptions, success/fail indications, filenames involved, and access control or flow control rules invoked.

Associating event types with detected events in the SUSE operating system audit logs provides a means of investigating an attack, recognizing resource utilization or capacity thresholds, or identifying an improperly configured SUSE operating system.

Satisfies: SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000359-GPOS-00146, SRG-OS-000365-GPOS-00152, SRG-OS-000474-GPOS-00219, SRG-OS-000475-GPOS-00220

V-217191

medium

Without establishing what type of events occurred, the source of events, where events occurred, and the outcome of events, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack.

Audit record content that may be necessary to satisfy this requirement includes, for example, time stamps, source and destination addresses, user/process identifiers, event descriptions, success/fail indications, filenames involved, and access control or flow control rules invoked.

Associating event types with detected events in the SUSE operating system audit logs provides a means of investigating an attack, recognizing resource utilization or capacity thresholds, or identifying an improperly configured SUSE operating system.

Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000122-GPOS-00063, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000392-GPOS-00172, SRG-OS-000480-GPOS-00227

V-217192

medium

To ensure SUSE operating systems have a sufficient storage capacity in which to write the audit logs, SUSE operating systems need to be able to allocate audit record storage capacity.

The task of allocating audit record storage capacity is usually performed during initial installation of the SUSE operating system.

V-217193

medium

If security personnel are not notified immediately when storage volume reaches 75 percent utilization, they are unable to plan for audit record storage capacity expansion.

V-217194

medium

It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without this notification, the security personnel may be unaware of an impending failure of the audit capability, and system operation may be adversely affected.

Audit processing failures include software/hardware errors, failures in the audit capturing mechanisms, and audit storage capacity being reached or exceeded.

This requirement applies to each audit data storage repository (i.e., distinct information system component where audit records are stored), the centralized audit storage capacity of organizations (i.e., all audit data storage repositories combined), or both.

V-217195

medium

V-217196

medium

It is critical that when the SUSE operating system is at risk of failing to process audit logs as required, it takes action to mitigate the failure. Audit processing failures include software/hardware errors, failures in the audit capturing mechanisms, and audit storage capacity being reached or exceeded. Responses to audit failure depend on the nature of the failure mode.

When availability is an overriding concern, other approved actions in response to an audit failure are as follows:

1) If the failure was caused by the lack of audit record storage capacity, the SUSE operating system must continue generating audit records if possible (automatically restarting the audit service if necessary), overwriting the oldest audit records in a first-in-first-out manner.

2) If audit records are sent to a centralized collection server and communication with this server is lost or the server fails, the SUSE operating system must queue audit records locally until communication is restored or until the audit records are retrieved manually. Upon restoration of the connection to the centralized collection server, action should be taken to synchronize the local audit data with the collection server.

V-217197

medium

Information stored in one location is vulnerable to accidental or incidental deletion or alteration.

Off-loading is a common process in information systems with limited audit storage capacity.

V-217198

low

Information stored in one location is vulnerable to accidental or incidental deletion or alteration.

Allowing devices and users to connect to or from the system without first authenticating them allows untrusted access and can lead to a compromise or attack. Audit events may include sensitive data must be encrypted prior to transmission. Kerberos provides a mechanism to provide both authentication and encryption for audit event records.

V-217199

low

Information stored in one location is vulnerable to accidental or incidental deletion or alteration.

Off-loading is a common process in information systems with limited audit storage capacity.

V-217200

medium

Information stored in one location is vulnerable to accidental or incidental deletion or alteration.

Off-loading is a common process in information systems with limited audit storage capacity.

V-217201

medium

Information stored in one location is vulnerable to accidental or incidental deletion or alteration.

Off-loading is a common process in information systems with limited audit storage capacity.

V-217202

medium

Without the capability to restrict which roles and individuals can select which events are audited, unauthorized personnel may be able to prevent the auditing of critical events. Misconfigured audits may degrade the system's performance by overwhelming the audit log. Misconfigured audits may also make it more difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one.

Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029

V-217203

medium

Protecting audit information also includes identifying and protecting the tools used to view and manipulate log data. Therefore, protecting audit tools is necessary to prevent unauthorized operation on audit information.

SUSE operating systems providing tools to interface with audit information will leverage user permissions and roles identifying the user accessing the tools and the corresponding rights the user enjoys to make access decisions regarding the access to audit tools.

Audit tools include but are not limited to vendor-provided and open-source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators.

Satisfies: SRG-OS-000256-GPOS-00097, SRG-OS-000257-GPOS-00098, SRG-OS-000258-GPOS-00099

V-217204

medium

By default, the SUSE operating system includes the "-a task,never" audit rule as a default. This rule suppresses syscall auditing for all tasks started with this rule in effect. Because the audit daemon processes the "audit.rules" file from the top down, this rule supersedes all other defined syscall rules; therefore no syscall auditing can take place on the operating system.

V-217205

medium

Once an attacker establishes initial access to a system, the attacker often attempts to create a persistent method of reestablishing access. One way to accomplish this is for the attacker to simply create a new account. Auditing of account creation mitigates this risk.

To address access requirements, many SUSE operating systems may be integrated with enterprise-level authentication/access/auditing mechanisms that meet or exceed access control policy requirements.

Satisfies: SRG-OS-000004-GPOS-00004, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000470-GPOS-00214, SRG-OS-000476-GPOS-00221

V-217206

medium

V-217207

medium

V-217208

medium

V-217209

low

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised information system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider threats and the advanced persistent threat.

Satisfies: SRG-OS-000327-GPOS-00127, SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000359-GPOS-00146, SRG-OS-000365-GPOS-00152

V-217210

medium

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one.

Audit records can be generated from various components within the information system (e.g., module or policy filter).

Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

V-217211

low

Reconstruction of harmful events or forensic analysis is not possible if audit records do not contain enough information.

At a minimum, the organization must audit the full-text recording of privileged commands. The organization must maintain audit trails in sufficient detail to reconstruct events to determine the cause and impact of compromise.

Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

V-217212

low

V-217213

low

V-217214

low

V-217215

low

V-217216

low

V-217217

medium

Without the capability to generate audit records, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one.

Audit records can be generated from various components within the information system (e.g., module or policy filter).

The list of audited events is the set of events for which audits are to be generated. This set of events is typically a subset of the list of all events for which the system is capable of generating audit records.

DoD has defined the following list of events for which the SUSE operating system will provide an audit record generation capability:

1) Successful and unsuccessful attempts to access, modify, or delete privileges, security objects, security levels, or categories of information (e.g., classification levels);

2) Access actions, such as successful and unsuccessful logon attempts, privileged activities or other system-level access, starting and ending time for user access to the system, concurrent logons from different workstations, successful and unsuccessful accesses to objects, all program initiations, and all direct access to the information system;

3) All account creations, modifications, disabling, and terminations; and

4) All kernel module load, unload, and restart actions.

Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

V-217218

medium

V-217219

medium

V-217220

medium

V-217221

medium

V-217222

medium

V-217223

medium

V-217224

medium

V-217225

medium

V-217226

medium

V-217227

medium

V-217228

medium

V-217229

medium

V-217230

medium

V-217231

medium

V-217232

medium

V-217233

medium

V-217234

medium

V-217235

medium

V-217236

low

V-217237

low

V-217238

low

V-217239

low

V-217240

medium

V-217241

medium

V-217242

medium

V-217243

medium

V-217244

medium

V-217245

medium

V-217246

medium

V-217247

medium

V-217248

medium

V-217249

medium

V-217250

medium

V-217251

medium

V-217252

medium

V-217253

medium

V-217254

medium

V-217255

medium

V-217256

medium

V-217257

medium

V-217258

medium

It is detrimental for SUSE operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors.

SUSE operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions and functions).

Examples of nonessential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but which cannot be disabled.

Satisfies: SRG-OS-000074-GPOS-00042, SRG-OS-000095-GPOS-00049

V-217260

medium

The banner must be acknowledged by the user prior to allowing the user access to the SUSE operating system. This provides assurance that the user has seen the message and accepted the conditions for access. If the consent banner is not acknowledged by the user, DoD will not be in compliance with system use notifications required by law.

To establish acceptance of the application usage policy, a click-through banner at system logon is required. The system must prevent further activity until the user executes a positive action to manifest agreement by clicking on a box indicating "OK".

V-217261

medium

To prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems.

SUSE operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component.

To support the requirements and principles of least functionality, the SUSE operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or address authorized quality-of-life issues.

Satisfies: SRG-OS-000096-GPOS-00050, SRG-OS-000297-GPOS-00115, SRG-OS-000480-GPOS-00231, SRG-OS-000480-GPOS-00232

V-217262

high

DoS is a condition when a resource is not available for legitimate users. When this occurs, the organization either cannot accomplish its mission or must operate at degraded capacity.

This requirement addresses the configuration of the SUSE operating system to mitigate the impact on system availability of DoS attacks that have occurred or are ongoing. For each system, known and potential DoS attacks must be identified and solutions for each type implemented. A variety of technologies exist to limit or, in some cases, eliminate the effects of DoS attacks (e.g., limiting processes or establishing memory partitions). Employing increased capacity and bandwidth, combined with service redundancy, may reduce the susceptibility to some DoS attacks.

V-217263

medium

Display of a standardized and approved use notification before granting access to the SUSE operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.

System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist.

The banner must be formatted in accordance with applicable DoD policy. Use the following verbiage for SUSE operating systems that can accommodate banners of 1300 characters:

"You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only.

By using this IS (which includes any device attached to this IS), you consent to the following conditions:

-The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations.

-At any time, the USG may inspect and seize data stored on this IS.

-Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose.

-This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy.

-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details."

Satisfies: SRG-OS-000228-GPOS-00088

V-217264

high

Without protection of the transmitted information, confidentiality and integrity may be compromised because unprotected communications can be intercepted and either read or altered.

This requirement applies to both internal and external networks and all types of information system components from which information can be transmitted (e.g., servers, mobile devices, notebook computers, printers, copiers, scanners, and facsimile machines). Communication paths outside the physical protection of a controlled boundary are exposed to the possibility of interception and modification.

Protecting the confidentiality and integrity of organizational information can be accomplished by physical means (e.g., employing physical distribution systems) or by logical means (e.g., employing cryptographic techniques). If physical means of protection are employed, logical means (cryptography) do not have to be employed, and vice versa.

Satisfies: SRG-OS-000423-GPOS-00187, SRG-OS-000424-GPOS-00188, SRG-OS-000425-GPOS-00189, SRG-OS-000426-GPOS-00190

V-217265

medium

Remote access services, such as those providing remote access to network devices and information systems, which lack automated monitoring capabilities, increase risk and make remote user access management difficult at best.

Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless.

Automated monitoring of remote access sessions allows organizations to detect cyber attacks and also ensure ongoing compliance with remote access policies by auditing connection activities of remote access capabilities, such as Remote Desktop Protocol (RDP), on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets).

V-217266

medium

Providing users with feedback on when account accesses via SSH last occurred facilitates user recognition and reporting of unauthorized account use.

V-217267

medium

To assure individual accountability and prevent unauthorized access, organizational users must be individually identified and authenticated.

A group authenticator is a generic account used by multiple individuals. Use of a group authenticator alone does not uniquely identify individual users. Examples of the group authenticator is the UNIX OS "root" user account, the Windows "Administrator" account, the "sa" account, or a "helpdesk" account.

For example, the UNIX and Windows SUSE operating systems offer a "switch user" capability, allowing users to authenticate with their individual credentials and, when needed, "switch" to the administrator role. This method provides for unique individual authentication prior to using a group authenticator.

Users (and any processes acting on behalf of users) need to be uniquely identified and authenticated for all accesses other than those accesses explicitly identified and documented by the organization, which outlines specific user actions that can be performed on the SUSE operating system without identification or authentication.

Requiring individuals to be authenticated with an individual authenticator prior to using a group authenticator allows for traceability of actions, as well as adding an additional level of protection of the actions that can be taken with group account knowledge.

V-217268

high

Failure to restrict system access via SSH to authenticated users negatively impacts SUSE operating system security.

V-217269

medium

SSH environment options potentially allow users to bypass access restriction in some configurations.

V-217270

medium

Without confidentiality protection mechanisms, unauthorized individuals may gain access to sensitive information via a remote access session.

Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless.

Encryption provides a means to secure the remote connection to prevent unauthorized access to the data traversing the remote access connection (e.g., RDP), thereby providing a degree of confidentiality. The encryption strength of a mechanism is selected based on the security categorization of the information.

The system will attempt to use the first cipher presented by the client that matches the server list. Listing the values "strongest to weakest" is a method to ensure the use of the strongest cipher available to secure the SSH connection.

Satisfies: SRG-OS-000033-GPOS-00014, SRG-OS-000120-GPOS-00061, SRG-OS-000125-GPOS-00065, SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173

V-217271

medium

Without cryptographic integrity protections, information can be altered by unauthorized users without detection.

Remote access (e.g., RDP) is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless.

Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash.

The system will attempt to use the first hash presented by the client that matches the server list. Listing the values "strongest to weakest" is a method to ensure the use of the strongest hash available to secure the SSH connection.

Satisfies: SRG-OS-000125-GPOS-00065, SRG-OS-000394-GPOS-00174

V-217272

medium

Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended. In addition, quickly terminating an idle session will also free up resources committed by the managed network element.

Terminating network connections associated with communications sessions includes, for example, deallocating associated TCP/IP address/port pairs at the SUSE operating system level, and deallocating networking assignments at the application level if multiple application sessions are using a single SUSE operating system-level network connection. This does not mean that the SUSE operating system terminates all sessions or network access; it only ends the inactive session and releases the resources associated with that session.

Satisfies: SRG-OS-000126-GPOS-00066, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109

V-217273

medium

Automatic session termination addresses the termination of user-initiated logical sessions in contrast to the termination of network connections that are associated with communications sessions (i.e., network disconnect). A logical session (for local, network, and remote access) is initiated whenever a user (or process acting on behalf of a user) accesses an organizational information system. Such user sessions can be terminated (and thus terminate user access) without terminating network sessions.

Session termination terminates all processes associated with a user's logical session except those processes that are specifically created by the user (i.e., session owner) to continue after the session is terminated.

Conditions or trigger events requiring automatic session termination can include, for example, organization-defined periods of user inactivity, targeted responses to certain types of incidents, and time-of-day restrictions on information system use.

This capability is typically reserved for specific SUSE operating system functionality where the system owner, data owner, or organization requires additional assurance.

V-217274

medium

Configuring this setting for the SSH daemon provides additional assurance that remote logon via SSH will require a password, even in the event of misconfiguration elsewhere.

V-217275

medium

If a public host key file is modified by an unauthorized user, the SSH service may be compromised.

V-217276

medium

If an unauthorized user obtains the private SSH host key file, the host could be impersonated.

V-217277

medium

If other users have access to modify user-specific SSH configuration files, they may be able to log on to the system as another user.

V-217278

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-217279

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-217280

medium

The security risk of using X11 forwarding is that the client's X11 display server may be exposed to attack when the SSH client requests forwarding. A system administrator may have a stance in which they want to protect clients that may expose themselves to attack by unwittingly requesting X11 forwarding, which can warrant a ''no'' setting.
X11 forwarding should be enabled with caution. Users with the ability to bypass file permissions on the remote host (for the user's X11 authorization database) can access the local X11 display through the forwarded connection. An attacker may then be able to perform activities such as keystroke monitoring if the ForwardX11Trusted option is also enabled.
If X11 services are not required for the system's intended function, they should be disabled or restricted as appropriate to the system’s needs.

V-217281

medium

Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside the configured acceptable allowance (drift) may be inaccurate.

Synchronizing internal information system clocks provides uniformity of time stamps for information systems with multiple system clocks and systems connected over a network.

Organizations should consider endpoints that may not have regular access to the authoritative time server (e.g., mobile, teleworking, and tactical endpoints).

Satisfies: SRG-OS-000355-GPOS-00143, SRG-OS-000356-GPOS-00144

V-217282

low

If time stamps are not consistently applied and there is no common time reference, it is difficult to perform forensic analysis.

Time stamps generated by the SUSE operating system include date and time. Time is commonly expressed in UTC, a modern continuation of GMT, or local time with an offset from UTC.

V-217283

medium

Some adversaries launch attacks with the intent of executing code in nonexecutable regions of memory or in memory locations that are prohibited. Security safeguards employed to protect memory include, for example, data execution prevention and address space layout randomization. Data execution prevention safeguards can either be hardware-enforced or software-enforced, with hardware providing the greater strength of mechanism.

Examples of attacks are buffer overflow attacks.

V-217284

medium

V-217285

medium

Information stored in one location is vulnerable to accidental or incidental deletion or alteration.

Off-loading is a common process in information systems with limited audit storage capacity.

V-217286

medium

Denial of Service (DoS) is a condition when a resource is not available for legitimate users. When this occurs, the organization either cannot accomplish its mission or must operate at degraded capacity.

Managing excess capacity ensures that sufficient capacity is available to counter flooding attacks. Employing increased capacity and service redundancy may reduce the susceptibility to some DoS attacks. Managing excess capacity may include, for example, establishing selected usage priorities, quotas, or partitioning.

V-217287

medium

Source-routed packets allow the source of the packet to suggest that 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-217288

medium

V-217289

medium

V-217290

medium

Responding to broadcast (ICMP) echoes facilitates network mapping and provides a vector for amplification attacks.

V-217291

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-217292

medium

V-217293

medium

V-217294

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, possibly revealing portions of the network topology.

V-217295

medium

V-217296

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-217297

medium

Network interfaces in promiscuous mode allow for the capture of all network traffic visible to the system. If unauthorized individuals can access these applications, it may allow then to collect information such as logon IDs, passwords, and key exchanges between systems.

If the system is being used to perform a network troubleshooting function, the use of these tools must be documented with the Information System Security Officer (ISSO) and restricted to only authorized personnel.

V-217298

medium

Without protection of communications with wireless peripherals, confidentiality and integrity may be compromised because unprotected communications can be intercepted and either read, altered, or used to compromise the SUSE operating system.

This requirement applies to wireless peripheral technologies (e.g., wireless mice, keyboards, displays, etc.) used with A SUSE operating system. Wireless peripherals (e.g., Wi-Fi/Bluetooth/IR Keyboards, Mice, and Pointing Devices and Near Field Communications [NFC]) present a unique challenge by creating an open, unsecured port on a computer. Wireless peripherals must meet DoD requirements for wireless data transmission and be approved for use by the AO. Even though some wireless peripherals, such as mice and pointing devices, do not ordinarily carry information that need to be protected, modification of communications with these wireless peripherals may be used to compromise the SUSE operating system. Communication paths outside the physical protection of a controlled boundary are exposed to the possibility of interception and modification.

Protecting the confidentiality and integrity of communications with wireless peripherals can be accomplished by physical means (e.g., employing physical barriers to wireless radio frequencies) or by logical means (e.g., employing cryptographic techniques). If physical means of protection are employed, then logical means (cryptography) do not have to be employed, and vice versa. If the wireless peripheral is only passing telemetry data, encryption of the data may not be required.

Satisfies: SRG-OS-000299-GPOS-00117, SRG-OS-000300-GPOS-00118, SRG-OS-000481-GPOS-000481

V-217299

medium

Using an authentication device, such as a CAC or token that is separate from the information system, ensures that even if the information system is compromised, that compromise will not affect credentials stored on the authentication device.

Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards such as the U.S. Government Personal Identity Verification card and the DoD Common Access Card.

A privileged account is defined as an information system account with authorizations of a privileged user.

Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless.

This requirement only applies to components where this is specific to the function of the device or has the concept of an organizational user (e.g., VPN, proxy capability). This does not apply to authentication for the purpose of configuring the device itself (management).

Satisfies: SRG-OS-000375-GPOS-00160, SRG-OS-000376-GPOS-00161, SRG-OS-000377-GPOS-00162

V-217300

medium

Using an authentication device, such as a Common Access Card (CAC) or token separate from the information system, ensures credentials stored on the authentication device will not be affected if the information system is compromised.

Multifactor solutions that require devices separate from information systems to gain access include: hardware tokens providing time-based or challenge-response authenticators, and smart cards such as the U.S. Government Personal Identity Verification (PIV) card and the DoD CAC.

A privileged account is defined as an information system account with authorizations of a privileged user.

Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless.

This requirement only applies to components with device-specific functions, or for organizational users (e.g., VPN, proxy capability). This does not apply to authentication for the purpose of configuring the device itself (management).

Satisfies: SRG-OS-000375-GPOS-00160, SRG-OS-000376-GPOS-00161, SRG-OS-000377-GPOS-00162

V-217301

medium

Using an authentication device, such as a CAC or token that is separate from the information system, ensures that even if the information system is compromised, that compromise will not affect credentials stored on the authentication device.

Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards such as the U.S. Government Personal Identity Verification card and the DoD Common Access Card.

A privileged account is defined as an information system account with authorizations of a privileged user.

Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless.

This requirement only applies to components where this is specific to the function of the device or has the concept of an organizational user (e.g., VPN, proxy capability). This does not apply to authentication for the purpose of configuring the device itself (management).

Satisfies: SRG-OS-000068-GPOS-00036, SRG-OS-000105-GPOS-00052, SRG-OS-000106-GPOS-00053, SRG-OS-000107-GPOS-00054, SRG-OS-000108-GPOS-00055, SRG-OS-000375-GPOS-00160, SRG-OS-000375-GPOS-00161, SRG-OS-000375-GPOS-00162

V-217302

medium

Without path validation, an informed trust decision by the relying party cannot be made when presented with any certificate not already explicitly trusted.

A trust anchor is an authoritative entity represented via a public key and associated data. It is used in the context of public key infrastructures, X.509 digital certificates, and DNSSEC.

When there is a chain of trust, usually the top entity to be trusted becomes the trust anchor; it can be, for example, a Certification Authority (CA). A certification path starts with the subject certificate and proceeds through a number of intermediate certificates up to a trusted root certificate, typically issued by a trusted CA.

This requirement verifies that a certification path to an accepted trust anchor is used for certificate validation and that the path includes status information. Path validation is necessary for a relying party to make an informed trust decision when presented with any certificate not already explicitly trusted. Status information for certification paths includes certificate revocation lists or online certificate status protocol responses. Validation of the certificate status information is out of scope for this requirement.

Satisfies: SRG-OS-000066-GPOS-00034, SRG-OS-000384-GPOS-00167

V-222385

medium

Adding endpoint security tools can provide the capability to automatically take actions in response to malicious behavior, which can provide additional agility in reacting to network threats. These tools also often include a reporting capability to provide network awareness of the system, which may not otherwise exist in an organization's systems management regime.

V-222386

high

Virus scanning software can be used to protect a system from penetration from computer viruses and to limit their spread through intermediate systems.

The virus scanning software should be configured to perform scans dynamically on accessed files. If this capability is not available, the system must be configured to scan, at a minimum, all altered files on the system on a daily basis.

If the system processes inbound SMTP mail, the virus scanner must be configured to scan all received mail.

V-233308

medium

When X11 forwarding is enabled, there may be additional exposure to the server and client displays if the sshd proxy display is configured to listen on the wildcard address. By default, sshd binds the forwarding server to the loopback address and sets the hostname part of the DIPSLAY environment variable to localhost. This prevents remote hosts from connecting to the proxy display.

V-237603

medium

The sudo command allows a user to execute programs with elevated (administrator) privileges. It prompts the user for their password and confirms your request to execute a command by checking a file, called sudoers. If the "sudoers" file is not configured correctly, any user defined on the system can initiate privileged actions on the target system.

V-237604

medium

The sudoers security policy requires that users authenticate themselves before they can use sudo. When sudoers requires authentication, it validates the invoking user's credentials. If the rootpw, targetpw, or runaspw flags are defined and not disabled, by default the operating system will prompt the invoking user for the "root" user password.
For more information on each of the listed configurations, reference the sudoers(5) manual page.

V-237605

medium

Without re-authentication, users may access resources or perform tasks for which they do not have authorization.

When operating systems provide the capability to escalate a functional capability, it is critical the organization requires the user to re-authenticate when using the "sudo" command.

If the value is set to an integer less than 0, the user's time stamp will not expire and the user will not have to re-authenticate for privileged actions until the user's session is terminated.

V-237606

medium

Accounts providing no operational purpose provide additional opportunities for system compromise. Therefore all necessary non-interactive accounts should not have an interactive shell assigned to them.

V-237607

medium

If the SUSE operating system were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process.

This requirement applies to SUSE operating systems with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs which execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.

V-237608

medium

V-237609

medium

V-237610

medium

V-237611

medium

V-237612

medium

V-237613

medium

V-237614

medium

V-237615

medium

V-237616

medium

V-237617

medium

V-237618

medium

V-237619

medium

It is detrimental for SUSE operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked, and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors.

SUSE operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions and functions).

Examples of nonessential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but which cannot be disabled.

V-237620

medium

V-237621

medium

V-237622

medium

V-237623

medium