Rule version UBTU-22-612020 · STIG v2 · 2026-09-09
Without the use of multifactor authentication, the ease of access to privileged functions is greatly increased.
Multifactor authentication requires using two or more factors to achieve authentication.
Factors include: 1) Something a user knows (e.g., password/PIN); 2) Something a user has (e.g., cryptographic identification device, token); and 3) Something a user is (e.g., biometric).
A privileged account is defined as an information system account with authorizations of a privileged user.
Network access is defined as access to an information system by a user (or a process acting on behalf of a user) communicating through a network (e.g., local area network, wide area network, or the internet).
The DoW common access card (CAC) with DoW-approved PKI is an example of multifactor authentication.
Satisfies: SRG-OS-000105-GPOS-00052, SRG-OS-000106-GPOS-00053, SRG-OS-000107-GPOS-00054, SRG-OS-000108-GPOS-00055
Verify that the "pam_pkcs11.so" module is configured by using the following command:
$ grep -i pam_pkcs11.so /etc/pam.d/common-auth
auth [success=3 default=ignore] pam_pkcs11.so If "pam_pkcs11.so" is commented out or is missing, this is a finding.
Verify the sshd daemon allows public key authentication by using the following command:
$ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH 'pubkeyauthentication'
/etc/ssh/sshd_config:PubkeyAuthentication yes If "PubkeyAuthentication" is not set to "yes" or is commented out or missing, or if conflicting results are returned, this is a finding.
Configure Ubuntu 22.04 LTS to use multifactor authentication for access to accounts.
Add or modify the following line in the "/etc/pam.d/common-auth" file:
auth [success=3 default=ignore] pam_pkcs11.so
Add or modify the following line in the "/etc/ssh/sshd_config" file:
PubkeyAuthentication yes