Information
Kerberos is a passwordless computer network security authentication protocol that was created by MIT to help solve network security problems
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 DoD data may be compromised.
Operating 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 DoD requirements. This allows for Security Levels 1, 2, 3, or 4 for use on a general-purpose computing system.
Solution
Configure the operating system to prevent system daemons from using Kerberos for authentication.
Run the following command to remove any files with the .keytab extension from the operating system:
# find /etc -mount -maxdepth 1 -type f -name '*.keytab' -exec rm -f {} +