What changed in Red Hat Enterprise Linux 8 STIG V2R9V2R9 changes

Discussion

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. Red Hat offers the Extended Update Support (EUS) add-on to a Red Hat Enterprise Linux subscription, for a fee, for those customers who wish to standardize on a specific minor release for an extended period. The RHEL 8 minor releases eligible for EUS are 8.1, 8.2, 8.4, 8.6, and 8.8. Each RHEL 8 EUS stream is available for 24 months from the availability of the minor release. RHEL 8.10 will be the final minor release overall. For more details on the Red Hat Enterprise Linux Life Cycle visit https://access.redhat.com/support/policy/updates/errata/. Note: The life-cycle time spans and dates are subject to adjustment. The version is still supported but has been superseded and must be removed from the enclave network or upgraded to a supported version. Red Hat Enterprise Linux 8 General Availability: May 7, 2019 Full Support: May 7, 2019 to May 31, 2024 Maintenance Support: Jun 1, 2024 to May 31, 2029 Extended Life Cycle (ELC): Jun 1, 2029 to May 31, 2033 Long-Life Add-On: Jun 1, 2033 to Ongoing Final Minor Release: 8.10

V-230221 in V2R9

Check text

Verify RHEL 8 is set to use a FIPS 140-3-compliant systemwide cryptographic policy. Verify the current systemwide crypto-policy with the following command: $ sudo update-crypto-policies --show FIPS:STIG If the systemwide crypto -policy is not set to "FIPS", this is a finding. Note: If subpolicies have been configured, they could be listed in a colon-separated list starting with "FIPS" as follows FIPS:&ltSUBPOLICY-NAME>. This is not a finding. Note: Subpolicies like AD-SUPPORT must be configured according to the latest guidance from the operating system vendor. Verify the current minimum crypto-policy configuration with the following commands: $ sudo grep -E 'rsa_size|hash' /etc/crypto-policies/state/CURRENT.pol hash = SHA2-256 SHA2-384 SHA2-512 SHA2-224 SHA3-256 SHA3-384 SHA3-512 min_rsa_size = 2048 If the "hash" values do not include at least the following FIPS 140-3-compliant algorithms, this is a finding: "SHA2-256 SHA2-384 SHA2-512 SHA2-224 SHA3-256 SHA3-384 SHA3-512", this is a finding. If thereany are algorithms that include "SHA1" or a hash value less than "224", this is a finding. If the "min_rsa_size" is not set to a value of at least "2048", this is a finding. If these commands do not return any output, this is a finding.

Fix text

Configure RHEL 8 to use a FIPS 140-3-compliant systemwide cryptographic policy. CreateSet a subpolicy for enhancements to the base systemwide crypto-policy by creating the file /etc/crypto-policies/policies/modules/STIG.pmod with the following content: # Define ciphers and MACs for OpenSSH and libssh cipher@SSH=AES-256-GCM AES-256-CTR AES-128-GCM AES-128-CTR mac@SSH=HMAC-SHA2-512 HMAC-SHA2-256 Apply the policy enhancements to the FIPS systemwide cryptographic policy level with the following command: $ sudo update-crypto-policies --set FIPS:STIG Setting system policy to FIPS Note: IfSystemwide additionalcrypto-policies subpolicies are beingapplied employed,on theyapplication muststartup. beIt addedis recommended to therestart update-crypto-policies command. To make the cryptographicsystem settings effective for alreadythe runningchange servicesof andpolicies applications,to restartfully thetake system: $ sudo rebootplace.

V-230223 in V2R9

Title

RHEL 8 must display the Standard Mandatory DODoW Notice and Consent Banner before granting local or remote access to the system via a ssh logon.

Check text

Verify any publicly accessible connection to the operating system displays the Standard Mandatory DODDoW Notice and Consent Banner before granting access to the system. Check for the location of the banner file being used with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '1r' | tr '1n' ' ' | xargs sudo grep -iH '^1s*banner' /etc/ssh/sshd_config:banner /etc/issue This command will return the banner keyword and the name of the file that contains the ssh banner (in this case "/etc/issue"). If the line is commented out, this is a finding. If conflicting results are returned, this is a finding. View the file specified by the banner keyword to check that it matches the text of the Standard Mandatory DODDoW Notice and Consent Banner: "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." If the system does not display a graphical logon banner or the banner does not match the Standard Mandatory DODDoW Notice and Consent Banner, this is a finding. If the text in the file does not match the Standard Mandatory DODDoW Notice and Consent Banner, this is a finding.

Fix text

Configure the operating system to display the Standard Mandatory DODDoW Notice and Consent Banner before granting access to the system via the ssh. Edit the "/etc/ssh/sshd_config" file to uncomment the banner keyword and configure it to point to a file that will contain the logon banner (this file may be named differently or be in a different location if using a version of SSH that is provided by a third-party vendor). An example configuration line is: banner /etc/issue Either create the file containing the banner or replace the text in the file with the Standard Mandatory DODDoW Notice and Consent Banner. The DODDoW-required text is: "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." The SSH service must be restarted for changes to take effect.

Discussion

Display of a standardized and approved use notification before granting access to the 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 DODDoW policy. Use the following verbiage for 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." Use the following verbiage for operating systems that have severe limitations on the number of characters that can be displayed in the banner: "I've read & consent to terms in IS user agreem't." Satisfies: SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088

V-230225 in V2R9

Title

RHEL 8 must display the Standard Mandatory DoDW Notice and Consent Banner before granting local or remote access to the system via a graphical user logon.

Check text

Verify RHEL 8 displays the Standard Mandatory DoDDoW Notice and Consent Banner before granting access to the operating system via a graphical user logon. Note: This requirement assumes the use of the RHEL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Check that the operating system displays the exact Standard Mandatory DoDDoW Notice and Consent Banner text with the command: $ sudo grep -r banner-message-text /etc/dconf/db/local.d/* /etc/dconf/db/local.d/01-banner-message:banner-message-text='You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only.1nBy using this IS (which includes any device attached to this IS), you consent to the following conditions:1n-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.1n-At any time, the USG may inspect and seize data stored on this IS.1n-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.1n-This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy.1n-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. ' Note: The "1n " characters are for formatting only. They will not be displayed on the graphical interface. If the banner does not match the Standard Mandatory DoDDoW Notice and Consent Banner exactly, this is a finding.

Fix text

Configure the operating system to display the Standard Mandatory DoDDoW Notice and Consent Banner before granting access to the system. Note: If the system does not have a graphical user interface installed, this requirement is Not Applicable. Add the following lines to the [org/gnome/login-screen] section of the "/etc/dconf/db/local.d/01-banner-message": banner-message-text='You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only.1nBy using this IS (which includes any device attached to this IS), you consent to the following conditions:1n-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.1n-At any time, the USG may inspect and seize data stored on this IS.1n-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.1n-This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy.1n-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. ' Note: The "1n " characters are for formatting only. They will not be displayed on the graphical interface. Run the following command to update the database: $ sudo dconf update

Discussion

Display of a standardized and approved use notification before granting access to the 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 DoDDoW policy. Use the following verbiage for 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-000023-GPOS-00006, SRG-OS-000228-GPOS-00088

V-230226 in V2R9

Title

RHEL 8 must display the Standard Mandatory DoDW Notice and Consent Banner before granting local or remote access to the system via a command line user logon.

Check text

Verify RHEL 8 displays the Standard Mandatory DoDDoW Notice and Consent Banner before granting access to the operating system via a command line user logon. Check that RHEL 8 displays a banner at the command line login screen with the following command: $ sudo cat /etc/issue If the banner is set correctly it will return the following text: "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." If the banner text does not match the Standard Mandatory DoDDoW Notice and Consent Banner exactly, this is a finding.

Fix text

Configure RHEL 8 to display the Standard Mandatory DoDDoW Notice and Consent Banner before granting access to the system via command line logon. Edit the "/etc/issue" file to replace the default text with the Standard Mandatory DoDDoW Notice and Consent Banner. The DoDDoW-required text is: "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."

Discussion

Display of a standardized and approved use notification before granting access to the 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 DoDDoW policy. Use the following verbiage for 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-000023-GPOS-00006, SRG-OS-000228-GPOS-00088

V-230227 in V2R9

Discussion

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 DODDoW 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 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-230228 in V2R9

Check text

Verify RHEL 8 for PKI-based authentication has valid certificates by constructing a certification path (which includes status information) to an accepted trust anchor. Note: If the Systemsystem Administratoradministrator demonstrates the use of an approved alternate multifactor authentication method, this requirement is not applicable. Check that the system has a valid DoDDoW root CA installed with the following command: $ sudo openssl x509 -text -in /etc/sssd/pki/sssd_auth_ca_db.pem Certificate: Data: Version: 3 (0x2) Serial Number: 1 (0x1) Signature Algorithm: sha256WithRSAEncryption Issuer: C = US, O = U.S. Government, OU = DoDDoW, OU = PKI, CN = DoD Root CA 3 Validity Not Before: Mar 20 18:46:41 2012 GMT Not After : Dec 30 18:46:41 2029 GMT Subject: C = US, O = U.S. Government, OU = DoDDoW, OU = PKI, CN = DoD Root CA 3 Subject Public Key Info: Public Key Algorithm: rsaEncryption If the root ca file is not a DoDDoW-issued certificate with a valid date and installed in the /etc/sssd/pki/sssd_auth_ca_db.pem location, this is a finding.

Fix text

Configure RHEL 8, for PKI-based authentication, to validate certificates by constructing a certification path (which includes status information) to an accepted trust anchor. Obtain a valid copy of the DoDDoW root CA file from the PKI CA certificate bundle at cyber.mil and copy into the following file: /etc/sssd/pki/sssd_auth_ca_db.pem

V-230229 in V2R9

Check text

Verify that the shadow password suite configuration is set to encrypt password with a FIPS 140-2 -approved cryptographic hashing algorithm. Check the hashing algorithm that is being used to hash passwords with the following command: $ sudo grep -i crypt /etc/login.defs ENCRYPT_METHOD SHA512 If "ENCRYPT_METHOD" does not equal SHA512 or greater, this is a finding.

Discussion

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. Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied upon to provide confidentiality or integrity, and DoDDoW data may be compromised. FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets DoDDoW requirements.

V-230231 in V2R9

Check text

Note: For systems that use BIOS, this is Not Applicable. Check tothe seeunified ifconfiguration anfile encryptedwhere grubthe superusersgrub2 password is setstored: # grep -iw "GRUB2_PASSWORD" /boot/grub2/user.cfg GRUB2_PASSWORD=grub.pbkdf2.sha512.[password_hash] If Onthe systems"GRUB2_PASSWORD" thatentry useexists UEFIand begins with "grub.pbkdf2.sha512", usethis theis followingnot command:a finding. $Note sudofor legacy RHEL 8 deployments: Older versions of RHEL 8 may have stored this file in the EFI partition. If the file is not found in `/boot/grub2/`, check the legacy UEFI path: # grep -iw grub2_passwordGRUB2_PASSWORD /boot/efi/EFI/redhat/user.cfg GRUB2_PASSWORD=grub.pbkdf2.sha512.[password_hash] If the grub"GRUB2_PASSWORD" superusersentry passworddoes not exist in either location, or does not begin with "grub.pbkdf2.sha512", this is a finding.

Fix text

Configure the system to require a grubGRUB bootloader password for the grub superusers account. Use with the "grub2-setpassword" command, which automatically creates/overwrites and sets the correct permissions for the unified "/boot/efigrub2/EFI/redhat/user.cfg" file. Generate anusing encryptedthe grub2required passwordPBKDF2 forSHA512 hashing algorithm. Generate the grubencrypted superusersGRUB account2 password with the following command: $# sudo grub2-setpassword Enter password: Confirm password: Note: Do not manually edit the GRUB configuration files to set this password; always use the provided utility to ensure the correct hashing algorithm is applied and the file is placed in the active configuration directory.

V-230234 in V2R9

Discussion

Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore, cannot be relied upon to provide confidentiality or integrity, and DoDDoW data may be compromised. RHEL 8 systems utilizing 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 utilize authentication that meets DoDDoW requirements. This allows for Security Levels 1, 2, 3, or 4 for use on a general-purpose computing system.

V-230237 in V2R9

Discussion

Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore, cannot be relied upon to provide confidentiality or integrity, and DoDDoW data may be compromised. RHEL 8 systems utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. The key derivation function (KDF) in Kerberos is not FIPS compatible. Ensuring the system does not have any keytab files present prevents system daemons from using Kerberos for authentication. A keytab is a file containing pairs of Kerberos principals and encrypted keys. FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets DoDDoW requirements. This allows for Security Levels 1, 2, 3, or 4 for use on a general-purpose computing system.

V-230238 in V2R9

Check text

Verify the krb5-workstation package has not been installed on the system with the following commands: If the system is a server or is utilizing krb5-workstation-1.17-18.el8.x86_64 or newer, this is Not Applicable. $ sudo yum list installed krb5-workstation krb5-workstation.x86_64 1.17-9.el8 repository If the krb5-workstation package is installed and is not documented with the Informationinformation Systemsystem Securitysecurity Officerofficer (ISSO) as an operational requirement, this is a finding.

Discussion

Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore, cannot be relied upon to provide confidentiality or integrity, and DoDDoW data may be compromised. RHEL 8 systems utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. Currently, Kerberos does not utilize FIPS 140-2 cryptography. FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets DoDDoW requirements. This allows for Security Levels 1, 2, 3, or 4 for use on a general-purpose computing system.

V-230239 in V2R9

Discussion

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, 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 DoDDoW 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-230243 in V2R9

Discussion

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DODDoW 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. RHEL 8 incorporates systemwide crypto policies by default. The SSH configuration file has no effect on the ciphers, MACs, or algorithms unless specifically defined in the /etc/sysconfig/sshd file. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/opensshserver.config file. Satisfies: SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, SRG-OS-000125-GPOS-00065

V-230251 in V2R9

Title

The RHEL 8 SSH server must be configured to use only DODDoW-approved encryption ciphers employing FIPS 140-3-validated cryptographic hash algorithms to protect the confidentiality of SSH server connections.

Discussion

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DODDoW 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. RHEL 8 incorporates systemwide crypto policies by default. The SSH configuration file has no effect on the ciphers, MACs, or algorithms unless specifically defined in the /etc/sysconfig/sshd file. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/opensshserver.config file. Satisfies: SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, SRG-OS-000125-GPOS-00065

V-230252 in V2R9

Check text

Verify the operating system prevents the installation of patches, service packs, device drivers, or operating system components from a repository without verification that they have been digitally signed using a certificate that is recognized and approved by the organization. Check that YUM verifies the signature of packages from a repository prior to install with the following command: $ sudo grep -E '^1[.*1]|gpgcheck' /etc/yum.repos.d/*.repo /etc/yum.repos.d/appstream.repo:[appstream] /etc/yum.repos.d/appstream.repo:gpgcheck=1 /etc/yum.repos.d/baseos.repo:[baseos] /etc/yum.repos.d/baseos.repo:gpgcheck=1 If "gpgcheck" is not set to "1", or if options are missing or commented out, ask the Systemsystem Administratoradministrator how the certificates for patches and other operating system components are verified. If there is no process to validate certificates that is approved by the organization, this is a finding.

Discussion

Changes to any software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor. Accordingly, patches, service packs, device drivers, or 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 verifies 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 operating system should not have to verify the software again. This requirement does not mandate DoDDoW certificates for this purpose; however, the certificate used to verify the software must be from an approved CA.

V-230264 in V2R9

Discussion

Changes to any software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor. Accordingly, patches, service packs, device drivers, or 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 verifies 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 operating system should not have to verify the software again. This requirement does not mandate DODDoW certificates for this purpose; however, the certificate used to verify the software must be from an approved CA.

V-230265 in V2R9

Discussion

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, 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 DoDDoW 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. Restricting access to the kernel message buffer limits access to only root. This prevents attackers from gaining additional system information as a non-privilegednonprivileged user. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

V-230269 in V2R9

Discussion

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, 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 DoDDoW 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. Setting the kernel.perf_event_paranoid kernel parameter to "2" prevents attackers from gaining additional system information as a non-privilegednonprivileged user. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

V-230270 in V2R9

Discussion

Using an authentication device, such as a DoDDoW Commoncommon Accessaccess Cardcard (CAC) or token that is separate from the information system, ensures that even if the information system is compromised, credentials stored on the authentication device will not be affected. 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 (PIV) card and the DoDDoW CAC. A privileged account is defined as an information system account with authorizations of a privileged user. Remote access is access to DoDDoW nonpublic information systems by an authorized user (or an information system) communicating through an external, nonnonorganization-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).

V-230273 in V2R9

Check text

Verify the operating system implements certificate status checking for multifactor authentication. Note: If the Systemsystem Administratoradministrator demonstrates the use of an approved alternate multifactor authentication method, this requirement is not applicable. CheckVerify to see if Online Certificate Status Protocol (OCSP) is enabled and using the proper digest value on the system with the following command: $ sudo grep certificate_verification /etc/sssd/sssd.conf /etc/sssd/conf.d/*.conf | grep -v "^#" certificate_verification = ocsp_dgst=sha1 If the certificate_verification line is missing from the [sssd] section, or is missing "ocsp_dgst=sha1", ask the administrator to indicate what type of multifactor authentication is being utilized and how the system implements certificate status checking. If there is no evidence of certificate status checking being used, this is a finding.

Discussion

Using an authentication device, such as a DoDDoW Commoncommon Accessaccess Cardcard (CAC) or token that is separate from the information system, ensures that even if the information system is compromised, credentials stored on the authentication device will not be affected. 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 (PIV) card and the DoDDoW CAC. RHEL 8 includes multiple options for configuring certificate status checking, but for this requirement focuses on the System Security Services Daemon (SSSD). By default, sssd performs Online Certificate Status Protocol (OCSP) checking and certificate verification using a sha256 digest function. Satisfies: SRG-OS-000375-GPOS-00160, SRG-OS-000377-GPOS-00162

V-230274 in V2R9

Discussion

The use of PIV credentials facilitates standardization and reduces the risk of unauthorized access. The DoDDoW has mandated the use of the Commoncommon Accessaccess Cardcard (CAC) to support identity management and personal authentication for systems covered under Homeland Security Presidential Directive (HSPD) 12, as well as making the CAC a primary component of layered protection for national security systems.

V-230275 in V2R9

Discussion

Configuring RHEL 8 to implement organization-wideorganizationwide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across the DoDDoW that reflects the most restrictive security posture consistent with operational requirements. Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the system, including the parameters required to satisfy other security control requirements. Security-related parameters include, for example: registry settings; account, file, directory permission settings; and settings for functions, ports, protocols, services, and remote connections.

V-230298 in V2R9

Title

RHEL 8 user account passwords must have a 6180-day maximum password lifetime restriction.

Check text

Verify that RHEL 8 enforces a 60180-day maximum password lifetime for new user accounts by running the following command: $ sudo grep -i pass_max_days /etc/login.defs PASS_MAX_DAYS 60180 If the "PASS_MAX_DAYS" parameter value is greater than "60180", or commented out, this is a finding.

Fix text

Configure RHEL 8 to enforce a 6180-day maximum password lifetime. Add, or modify the following line in the "/etc/login.defs" file: PASS_MAX_DAYS 6180

V-230366 in V2R9

Title

RHEL 8 user account passwords must be configured so that existing passwords are restricted to a 6180-day maximum lifetime.

Check text

Check whether the maximum time period for existing passwords is restricted to 60180 days with the following commands: $ sudo awk -F: '$5 > 60180 {print $1 " " $5}' /etc/shadow $ sudo awk -F: '$5 &lt= 0 {print $1 " " $5}' /etc/shadow If any results are returned that are not associated with a system account, this is a finding.

Fix text

Configure non-compliant accounts to enforce a 6180-day maximum password lifetime restriction. $ sudo chage -M 6180 [user]

V-230367 in V2R9

Discussion

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 to determine strength and how long it takes to crack a password. Use of more characters in a password helps to increase exponentially the time and/or resources required to compromise the password. RHEL 8 utilizes "pwquality" as a mechanism to enforce password complexity. Configurations are set in the "etc/security/pwquality.conf" file. The "minlen", sometimes noted as minimum length, acts as a "score" of complexity based on the credit components of the "pwquality" module. By setting the credit components to a negative value, not only will those components be required, they will not count towards the total "score" of "minlen". This will enable "minlen" to require a 15-character minimum. The DoDDoW minimum password requirement is 15 characters.

V-230369 in V2R9

Discussion

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 to determine strength and how long it takes to crack a password. Use of more characters in a password helps to increase exponentially the time and/or resources required to compromise the password. The DoDDoW minimum password requirement is 15 characters.

V-230370 in V2R9

Check text

Verify RHEL 8 uses multifactor authentication for local access to accounts. Note: If the Systemsystem Administratoradministrator demonstrates the use of an approved alternate multifactor authentication method, this requirement is not applicable. Check that the "pam_cert_auth" setting is set to "true" in the "/etc/sssd/sssd.conf" file. Check that the "try_cert_auth" or "require_cert_auth" options are configured in both "/etc/pam.d/system-auth" and "/etc/pam.d/smartcard-auth" files with the following command: $ sudo grep -ir cert_auth /etc/sssd/sssd.conf /etc/sssd/conf.d/*.conf /etc/pam.d/* /etc/sssd/sssd.conf:pam_cert_auth = True /etc/pam.d/smartcard-auth:auth sufficient pam_sss.so try_cert_auth /etc/pam.d/system-auth:auth [success=done authinfo_unavail=ignore ignore=ignore default=die] pam_sss.so try_cert_auth If "pam_cert_auth" is not set to "true" in "/etc/sssd/sssd.conf", this is a finding. If "pam_sss.so" is not set to "try_cert_auth" or "require_cert_auth" in both the "/etc/pam.d/smartcard-auth" and "/etc/pam.d/system-auth" files, this is a finding.

Discussion

Using an authentication device, such as a Commoncommon Accessaccess CardCcard (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 DoDDoW CAC. There are various methods of implementing multifactor authentication for RHEL 8. Some methods include a local system multifactor account mapping or joining the system to a domain and utilizing a Red Hat idM server or Microsoft Windows Active Directory server. Any of these methods will require that the client operating system handle the multifactor authentication correctly. Satisfies: SRG-OS-000105-GPOS-00052, SRG-OS-000106-GPOS-00053, SRG-OS-000107-GPOS-00054, SRG-OS-000108-GPOS-00055

V-230372 in V2R9

Fix text

Configure RHEL 8 to disable account identifiers after 35 days of inactivity after the password expiration. Run the following command to change the configuration for useradd: $ sudo useradd -D -f 35 DoDDoW recommendation is 35 days, but a lower value is acceptable. The value "-1" will disable this feature, and "0" will disable the account immediately after the password expires.

V-230373 in V2R9

Discussion

Configuring the operating system to implement organization-wide security implementation guides and security checklists verifies compliance with federal standards and establishes a common security baseline across the DoDDoW that reflects the most restrictive security posture consistent with operational requirements. Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the system, including the parameters required to satisfy other security control requirements. Security-related parameters include, for example, registry settings; account, file, and directory permission settings; and settings for functions, ports, protocols, services, and remote connections.

V-230378 in V2R9

Discussion

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 "kmod" command is used to control Linux Kernel modules. 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. DoDDoW has defined the list of events for which RHEL 8 will provide an audit record generation capability as the following: 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-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222

V-230465 in V2R9

Discussion

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. DoDDoW has defined the list of events for which RHEL 8 will provide an audit record generation capability as the following: 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. From "Pam_Faillock man" pages: Note the default directory that pam_faillock uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218

V-230466 in V2R9

Discussion

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. DoDDoW has defined the list of events for which RHEL 8 will provide an audit record generation capability as the following: 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-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218

V-230467 in V2R9

Discussion

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. If auditing is enabled late in the startup process, the actions of some startup processes may not be audited. Some audit systems also maintain state information only available if auditing is enabled before a given process is created. 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. DoDDoW has defined the list of events for which RHEL 8 will provide an audit record generation capability as the following: 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-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218

V-230468 in V2R9

Discussion

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. If auditing is enabled late in the startup process, the actions of some startup processes may not be audited. Some audit systems also maintain state information only available if auditing is enabled before a given process is created. 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. DoDDoW has defined the list of events for which RHEL 8 will provide an audit record generation capability as the following: 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-000062-GPOS-00031, SRG-OS-000471-GPOS-00215

V-230470 in V2R9

Check text

Verify that the files in the directory "/etc/audit/rules.d/" and "/etc/audit/auditd.conf" file have a mode of "0600" or less permissive bywith using the following commandscommand: $ sudo find /etc/audit/rules.d/ -type f -name "*.rules" -exec lsstat -alc "%a %n" {} 1; -rw-------.600 1 root root 284 May 1 20:30 /etc/audit/rules.d/audit.rules $Verify sudothat lsthe -lfiles /etc/audit/audit.rules and /etc/audit/auditd.conf -rw------- 1have roota rootmode 621of Sep0600 22or 17:19less auditd.confpermissive with the following command: If$ thesudo filesstat in-c the"%a %n" /etc/audit/audit.rules /etc/audit/auditd.dconf 600 /"etc/audit/audit.rules 600 directory or the "/etc/audit/auditd.conf" If fileany of the audit configuration files have a mode more permissive than "0600", this is a finding.

Fix text

Configure the rules files in the directory "/etc/audit/rules.d/", the /etc/audit/audit.rules file, and the "/etc/audit/auditd.conf" file to have a mode of "0600" with the following commands: $ sudo chmodfind 0600 /etc/audit/rules.d/audit -type f -name "*.rules" -exec chmod 0600 {} + $ sudo chmod 0600 /etc/audit/rulesaudit.d/[customrulesfile].rules $ sudo chmod 0600 /etc/audit/auditd.conf

V-230471 in V2R9

Title

RHEL 8 must securely compare internal information system clocks at least every 24 hours with a server synchronized to an authoritative time source, such as the United States Naval Observatory (USNO) time servers, or a time server designated for the appropriate DoDDoW network (NIPRNet/SIPRNet), and/or the Global Positioning System (GPS).

Check text

Verify RHEL 8 is securely comparing internal information system clocks at least every 24 hours with an NTP server with the following commands: $ sudo grep maxpoll /etc/chrony.conf server 0.us.pool.ntp.mil iburst maxpoll 16 If the "maxpoll" option is set to a number greater than 16 or the line is commented out, this is a finding. Verify the "chrony.conf" file is configured to an authoritative DoDDoW time source by running the following command: $ sudo grep -i server /etc/chrony.conf server 0.us.pool.ntp.mil If the parameter "server" is not set or is not set to an authoritative DoDDoW time source, this is a finding.

Discussion

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). 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 operating system include date and time. Time is commonly expressed in Coordinated Universal Time (UTC), a modern continuation of Greenwich Mean Time (GMT), or local time with an offset from UTC. RHEL 8 utilizes the "timedatectl" command to view the status of the "systemd-timesyncd.service". The "timedatectl" status will display the local time, UTC, and the offset from UTC. Note that USNO offers authenticated NTP service to DoDDoW and U.S. Government agencies operating on the NIPR and SIPR networks. Visit https://www.usno.navy.mil/USNO/time/ntp/dodDoW-customers for more information. Satisfies: SRG-OS-000355-GPOS-00143, SRG-OS-000356-GPOS-00144, SRG-OS-000359-GPOS-00146

V-230484 in V2R9

Discussion

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. Minimizing the exposure of the server functionality of the chrony daemon diminishes the attack surface. RHEL 8 utilizes the "timedatectl" command to view the status of the "systemd-timesyncd.service". The "timedatectl" status will display the local time, Coordinated Universal Time (UTC), and the offset from UTC. Note that USNO offers authenticated NTP service to DODDoW and U.S. Government agencies operating on the NIPR and SIPR networks. Visit https://www.usno.navy.mil/USNO/time/ntp/DODDoW-customers for more information.

V-230485 in V2R9

Discussion

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. Not exposing the management interface of the chrony daemon on the network diminishes the attack space. RHEL 8 utilizes the "timedatectl" command to view the status of the "systemd-timesyncd.service". The "timedatectl" status will display the local time, Coordinated Universal Time (UTC), and the offset from UTC. Note that USNO offers authenticated NTP service to DODDoW and U.S. Government agencies operating on the NIPR and SIPR networks. Visit https://www.usno.navy.mil/USNO/time/ntp/DODDoW-customers for more information.

V-230486 in V2R9

Fix text

Configure the operating system to disable the built-in or attached camera when not in use. Add or update the followindfollowing lines in the "/etc/modprobe.d/blacklist.conf" file: install uvcvideo /bin/false blacklist uvcvideo Reboot the system for the settings to take effect.

V-230493 in V2R9

Check text

Verify "firewalld" is configured to employ a deny-all, allow-by-exception policy for allowing connections to other systems with the following commands: $ sudo firewall-cmd --state running $ sudo firewall-cmd --get-active-zones [custom] interfaces: ens33 $ sudo firewall-cmd --info-zone=[custom] | grep target target: DROP If no zones are active on the RHEL 8 interfaces or if the target is set to a different option other than "DROP", this is a finding. If the "firewalld" package is not installed, ask the Systemsystem Administratoradministrator if an alternate firewall (such as iptables) is installed and in use, and how is it configured to employ a deny-all, allow-by-exception policy. If the alternate firewall is not configured to employ a deny-all, allow-by-exception policy, this is a finding. If no firewall is installed, this is a finding.

Discussion

Failure to restrict network connectivity only to authorized systems permits inbound connections from malicious systems. It also permits outbound connections that may facilitate exfiltration of DoDDoW data. RHEL 8 incorporates the "firewalld" daemon, which allows for many different configurations. One of these configurations is zones. Zones can be utilized to a deny-all, allow-by-exception approach. The default "drop" zone will drop all incoming network packets unless it is explicitly allowed by the configuration file or is related to an outgoing network connection.

V-230504 in V2R9

Check text

Verify that "firewalld" is installed with the following commands: $ sudo yum list installed firewalld firewalld.noarch 0.7.0-5.el8 If the "firewalld" package is not installed, ask the Systemsystem Administratoradministrator if another firewall is installed. If no firewall is installed this is a finding.

Discussion

"Firewalld" provides an easy and effective way to block/limit remote access to the system via ports, services, and protocols. Remote access services, such as those providing remote access to network devices and information systems, which lack automated control capabilities, increase risk and make remote user access management difficult at best. Remote access is access to DoDDoW nonpublic information systems by an authorized user (or an information system) communicating through an external, nonnonorganization-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. RHEL 8 functionality (e.g., RDP) must be capable of taking enforcement action if the audit reveals unauthorized activity. Automated control of remote access sessions allows organizations to ensure ongoing compliance with remote access policies by enforcing connection rules of remote access applications on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets).

V-230505 in V2R9

Check text

Verify there are no wireless interfaces configured on the system with the following command: Note: This requirement is Not Applicable for systems that do not have physical wireless network radios. $ sudo nmcli device status DEVICE TYPE STATE CONNECTION virbr0 bridge connected virbr0 wlp7s0 wifi connected wifiSSID enp6s0 ethernet disconnected -- p2p-dev-wlp7s0 wifi-p2p disconnected -- lo loopback unmanaged -- virbr0-nic tun unmanaged -- If a wireless interface is configured and has not been documented and approved by the Informationinformation Systemsystem Securitysecurity Officerofficer (ISSO), this is a finding.

Discussion

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 RHEL 8 operating system. This requirement applies to wireless peripheral technologies (e.g., wireless mice, keyboards, displays, etc.) used with RHEL 8 systems. 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 DoDDoW requirements for wireless data transmission and be approved for use by the Authorizingauthorizing Officialofficial (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 RHEL 8 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-230506 in V2R9

Check text

If the device or operating system does not have a Bluetooth adapter installed, this requirement is not applicable. This requirement is not applicable to mobile devices (smartphones and tablets), where the use of Bluetooth is a local AO decision. Determine if Bluetooth is disabled with the following command: $ sudo grep bluetooth /etc/modprobe.d/* /etc/modprobe.d/bluetooth.conf:install bluetooth /bin/false If the Bluetooth driver blacklist entry is missing, a Bluetooth driver is determined to be in use, and the collaborative computing device has not been authorized for use, this is a finding. Verify the operating system disables the ability to use Bluetooth with the following command: $ sudo grep -r bluetooth /etc/modprobe.d | grep -i "blacklist" | grep -v "^#" blacklist bluetooth If the command does not return any output or the output is not "blacklist bluetooth", and use of Bluetooth is not documented with the information system securiy officer (ISSO) as an operational requirement, this is a finding.

Discussion

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 RHEL 8 operating system. This requirement applies to wireless peripheral technologies (e.g., wireless mice, keyboards, displays, etc.) used with RHEL 8 systems. 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 DoDDoW requirements for wireless data transmission and be approved for use by the Authorizingauthorizing Officialofficial (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 RHEL 8 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.

V-230507 in V2R9

Fix text

Configure RHEL 8 to disable the CtrlAltDelBurstAction by adding it to a drop file in a "/etc/systemd/system.conf.d/" configuration file: If no drop file exists, create one with the following command: $ sudo mkdir -p /etc/systemd/system.conf.d && sudo vi /etc/systemd/system.conf.d/55-CtrlAltDel-BurstAction.conf Edit the file to contain the setting by adding the following text: [Manager] CtrlAltDelBurstAction=none Reload the daemon for this change to take effect. $ sudo systemctl daemon-reload

V-230531 in V2R9

Check text

Verify the krb5-server package has not been installed on the system with the following commands: If the system is a workstation or is utilizing krb5-server-1.17-18.el8.x86_64 or newer, this is Not Applicable $ sudo yum list installed krb5-server krb5-server.x86_64 1.17-9.el8 repository If the krb5-server package is installed and is not documented with the Informationinformation Systemsystem Securitysecurity Officerofficer (ISSO) as an operational requirement, this is a finding.

Discussion

Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore, cannot be relied upon to provide confidentiality or integrity, and DoDDoW data may be compromised. RHEL 8 systems utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. Currently, Kerberos does not utilize FIPS 140-2 cryptography. FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets DoDDoW requirements. This allows for Security Levels 1, 2, 3, or 4 for use on a general-purpose computing system.

V-237640 in V2R9

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Verify the operating system requires re-authentication when using the "sudo" command to elevate privileges. $ sudo grep -ir 'timestamp_timeout' /etc/sudoers /etc/sudoers.d /etc/sudoers:Defaults timestamp_timeout=0 If conflicting results are returned from more than one file location, this is a finding. If "timestamp_timeout" is set to a value other than "0" (including negative numbernumbers), is commented out, or nois resultsmissing are returnedentirely, this is a finding.

Fix text

Configure the "sudo"OS command to requirereauthenticate re-authentication. Editevery theinvocation /etc/sudoersof file: $the "sudo" visudocommand. Add or modify the following line: Defaults timestamp_timeout=[value] Note:to The "[value]/etc/sudoers" mustor be a numberfile thatin is greater than or equal to "0"/etc/sudoers.d": Defaults timestamp_timeout=0 Remove any duplicate or conflicting lines from /etc/sudoers and /etc/sudoersdefinitions.d/ files.

V-237643 in V2R9

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Note: For systems that use BIOS, this is Not Applicable. Verify that a unique name is set as the "superusers" account:. $Search sudothe unified GRUB 2 configuration file for the superusers definition: # grep -iw "superusers" /boot/efigrub2/EFI/redhat/grub.cfg set superusers="[someuniquestringhere]" export superusers If "superusers" is not defined, or if the defined superuser name is identical to anya standard OS administrative account name or(such isas missing"root", a"admin", name"administrator", "superuser", or "unlock"), this is a finding. Note for legacy RHEL 8 deployments: If the system is running an older minor release where GRUB paths are not unified, check the legacy UEFI path: # grep -iw "superusers" /boot/boot/efi/EFI/redhat/grub.cfg

Fix text

Configure the system to have a unique name for the grubGRUB 2 superusers account. 1. Edit the "/etc/grub.[...](asc_slot://start-slot-10)d/01_users" file andto adddeclare orthe modifycustom superuser name: # pfedit /etc/grub.d/01_users Ensure the following lines exist or are modified: set superusers="[someuniquestringhere]" export superusers password_pbkdf2 [someuniquestringhere] ${GRUB2_PASSWORD} Generate(Replace "[someuniquestringhere]" with a newunique string that does not match any existing OS user account name.) 2. Regenerate the GRUB 2 configuration using the unified configuration utility: # grub2-mkconfig -o /boot/grub2/grub.cfg Note for legacy RHEL 8 deployments: If using an older minor release requiring the legacy partition file withpath, output the followingconfig commandto: $# sudo grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg

Discussion

If the system does not require valid authentication 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. GRUB 2 is the default boot loader for RHEL 8 and is designed to require a password to boot into single-user mode or make modifications to the boot menu. The GRUB 2 superuser account is an account of last resort. Establishing a unique username for this account hardens the boot loader against brute force attacks. Due to the nature of the superuser account database being distinct from the OS account database, this allows the use of a username that is not among those within the OS account database. Examples of non-uniquenonunique superusers names are root, superuser, unlock, etc.

V-244521 in V2R9

Discussion

Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore, cannot be relied upon to provide confidentiality or integrity, and DoDDoW data may be compromised. RHEL 8 systems utilizing 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 utilize authentication that meets DoDDoW requirements. This allows for Security Levels 1, 2, 3, or 4 for use on a general-purpose computing system.

V-244524 in V2R9

Check text

Verify that "firewalld" is active with the following commands: $ sudo systemctl is-active firewalld active If the "firewalld" package is not "active", ask the Systemsystem Administratoradministrator if another firewall is installed. If no firewall is installed and active this is a finding.

Discussion

"Firewalld" provides an easy and effective way to block/limit remote access to the system via ports, services, and protocols. Remote access services, such as those providing remote access to network devices and information systems, which lack automated control capabilities, increase risk and make remote user access management difficult at best. Remote access is access to DoDDoW nonpublic information systems by an authorized user (or an information system) communicating through an external, nonnonorganization-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. RHEL 8 functionality (e.g., RDP) must be capable of taking enforcement action if the audit reveals unauthorized activity. Automated control of remote access sessions allows organizations to ensure ongoing compliance with remote access policies by enforcing connection rules of remote access applications on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets).

V-244544 in V2R9

Check text

Verify the operating system uses "pwquality" to enforce the password complexity rules. Check for the use of "pwquality" in the system-auth file with the following command: $ sudo cat /etc/pam.d/system-auth | grep pam_pwquality password requisiterequired pam_pwquality.so If the command does not return a line containing the value "pam_pwquality.so" as shown, or the line is commented out, this is a finding.

Fix text

Configure the operating system to use "pwquality" to enforce password complexity rules. Add the following line to the "/etc/pam.d/system-auth" file (or modify the line to have the required value): password requisiterequired pam_pwquality.so

V-251713 in V2R9

Title

The RHEL 8 SSH client must be configured to use only DODDoW-approved Message Authentication Codes (MACs) employing FIPS 140-3-validated cryptographic hash algorithms to protect the confidentiality of SSH client connections.

Discussion

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DODDoW 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. RHEL 8 incorporates systemwide crypto policies by default. The SSH configuration file has no effect on the ciphers, MACs, or algorithms unless specifically defined in the /etc/sysconfig/sshd file. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/openssh.config file.

V-272482 in V2R9

Title

The RHEL 8 SSH client must be configured to use only DODDoW-approved encryption ciphers employing FIPS 140-3-validated cryptographic hash algorithms to protect the confidentiality of SSH client connections.

Discussion

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DODDoW 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. RHEL 8 incorporates systemwide crypto policies by default. The SSH configuration file has no effect on the ciphers, MACs, or algorithms unless specifically defined in the /etc/sysconfig/sshd file. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/openssh.config file. Satisfies: SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, SRG-OS-000125-GPOS-00066

V-272483 in V2R9

Title

RHEL 8 must implement DODoW-approved encryption in the bind package.

V-279931 in V2R9

Discussion

The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected. 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, 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 DODDoW 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. Restricting access to the kernel message buffer limits access to only root. This prevents attackers from gaining additional system information as a nonprivileged user. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographical order, regardless of the directories in which they reside. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

V-284948 in V2R9

Discussion

The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected. 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, 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 DODDoW 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. Restricting access to the kernel message buffer limits access to only root. This prevents attackers from gaining additional system information as a nonprivileged user. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographical order, regardless of the directories in which they reside. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

V-284949 in V2R9