Vulnerability Discussion

The system must be configured to enforce multifactor authentication.

All users must go through multifactor authentication to prevent unauthenticated access and potential compromise to the system.

IMPORTANT: Modification of Pluggable Authentication Modules (PAM) now requires user authorization or use of a Privacy Preferences Policy Control (PPPC) profile from MDM that authorizes modifying system administrator files or full disk access.

NOTE: /etc/pam.d/login will be automatically modified to its original state following any update or major upgrade to the operating system.

Satisfies: SRG-OS-000105-GPOS-00052, SRG-OS-000106-GPOS-00053, SRG-OS-000107-GPOS-00054, SRG-OS-000108-GPOS-00055, SRG-OS-000112-GPOS-00057, SRG-OS-000705-GPOS-00150

Check

Verify the macOS system is configured to enforce multifactor authentication for login with the following command:

/usr/bin/grep -Ec '^(auth\s+sufficient\s+pam_smartcard.so|auth\s+required\s+pam_deny.so)' /etc/pam.d/login

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

Fix

Configure the macOS system to enforce multifactor authentication for login with the following commands:

/bin/cat > /etc/pam.d/login << LOGIN_END
# login: auth account password session
auth sufficient pam_smartcard.so
auth optional pam_krb5.so use_kcminit
auth optional pam_ntlm.so try_first_pass
auth optional pam_mount.so try_first_pass
auth required pam_opendirectory.so try_first_pass
auth required pam_deny.so
account required pam_nologin.so
account required pam_opendirectory.so
password required pam_opendirectory.so
session required pam_launchd.so
session required pam_uwtmp.so
session optional pam_mount.so
LOGIN_END

/bin/chmod 644 /etc/pam.d/login
/usr/sbin/chown root:wheel /etc/pam.d/login