STIG ID: UBTU-20-010033 | SRG: SRG-OS-000105-GPOS-00052 | Severity: medium | CCI: | Vulnerability Id: V-238210
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 DoD CAC with DoD-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
Configure the Ubuntu operating system to use multifactor authentication for network access to accounts.
Add or update "pam_pkcs11.so" in "/etc/pam.d/common-auth" to match the following line:
auth [success=2 default=ignore] pam_pkcs11.so
Set the sshd option "PubkeyAuthentication yes" in the "/etc/ssh/sshd_config" file.
Verify the Ubuntu operating system has the packages required for multifactor authentication installed with the following commands:
$ dpkg -l | grep libpam-pkcs11
ii libpam-pkcs11 0.6.8-4 amd64 Fully featured PAM module for using PKCS#11 smart cards
If the "libpam-pkcs11" package is not installed, this is a finding.
Verify the sshd daemon allows public key authentication with the following,
$ grep ^Pubkeyauthentication /etc/ssh/sshd_config
PubkeyAuthentication yes
If this option is set to "no" or is missing, this is a finding.