Vulnerability Discussion

If cached authentication information is out-of-date, the validity of the authentication information may be questionable.

RHEL 8 includes multiple options for configuring authentication, but this requirement will be focus on the System Security Services Daemon (SSSD). By default sssd does not cache credentials.

Check

Verify that the SSSD prohibits the use of cached authentications after one day.

Note: If smart card authentication is not being used on the system this item is Not Applicable.

Check that SSSD allows cached authentications with the following command:

$ sudo grep -ir cache_credentials /etc/sssd/sssd.conf /etc/sssd/conf.d/*.conf
cache_credentials = true

If "cache_credentials" is set to "false" or missing from the configuration file, this is not a finding and no further checks are required.

If "cache_credentials" is set to "true", check that SSSD prohibits the use of cached authentications after one day with the following command:

$ sudo grep -ir offline_credentials_expiration /etc/sssd/sssd.conf /etc/sssd/conf.d/*.conf
offline_credentials_expiration = 1

If "offline_credentials_expiration" is not set to a value of "1", this is a finding.

Fix

Configure the SSSD to prohibit the use of cached authentications after one day.

Add or change the following line in "/etc/sssd/sssd.conf" just below the line "[pam]".

offline_credentials_expiration = 1