Vulnerability Discussion

The macOS system must be configured to block access to users who are no longer authorized (i.e., users with revoked certificates).

To prevent the use of untrusted certificates, the certificates on a smart card must meet the following criteria: its issuer has a system-trusted certificate, the certificate is not expired, its "valid-after" date is in the past, and it passes Certificate Revocation List (CRL) and Online Certificate Status Protocol (OCSP) checking.

By setting the smart card certificate trust level to moderate, the system will execute a soft revocation, i.e., if the OCSP/CRL server is unreachable, authentication will still succeed.

Note: Before applying this setting, refer to the smart card supplemental guidance.

Satisfies: SRG-OS-000066-GPOS-00034,SRG-OS-000377-GPOS-00162,SRG-OS-000384-GPOS-00167,SRG-OS-000403-GPOS-00182

Check

Verify the macOS system is configured to check the revocation status of user certificates with the following command:

/usr/bin/osascript -l JavaScript << EOS
$.NSUserDefaults.alloc.initWithSuiteName('com.apple.security.smartcard')\
.objectForKey('checkCertificateTrust').js
EOS

If the result is not "2", this is a finding.

Fix

Configure the macOS system to check the revocation status of user certificates by installing the "com.apple.security.smartcard" configuration profile.

Note: To ensure continued access to the operating system, consult the supplemental guidance provided with the STIG before applying the configuration profile.