Title

RHEL 9 must prevent system daemons from using Kerberos for authentication. (Cat II impact)

Discussion

Unapproved mechanisms used for authentication to the cryptographic module are not verified; therefore, cannot be relied upon to provide confidentiality or integrity and DOD data may be compromised. RHEL 9 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 140-3 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets DOD requirements. This allows for Security Levels 1, 2, 3, or 4 for use on a general-purpose computing system.

Check Content

Note: If there is an operational requirement for Kerberos implementation, and it is documented with the ISSO, this control is Not Applicable. Verify that RHEL 9 prevents system daemons from using Kerberos for authentication with the following command: $ sudo ls -al /etc/*.keytab ls: cannot access '/etc/*.keytab': No such file or directory If this command produces any "keytab" file(s), this is a finding.

Fix Text

Configure RHEL 9 to prevent system daemons from using Kerberos for authentication. Remove any files with the .keytab extension from the operating system. rm -f /etc/*.keytab If Kerberos authentication is a mission requirement, document its use and justification with the ISSO.

Additional Identifiers

Rule ID: SV-258130r1045258_rule

Vulnerability ID: V-258130

Group Title: SRG-OS-000120-GPOS-00061

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.