STIG ID: ALMA-09-033240 | SRG: SRG-OS-000105-GPOS-00052 | Severity: medium | CCI: | Vulnerability Id: V-269367
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.
Configure the SSH daemon to accept public key encryption.
Add the following line to "/etc/ssh/sshd_config", or uncomment the line and set the value to "yes":
PubkeyAuthentication yes
Alternatively, add the setting to an include file if the line "Include /etc/ssh/sshd_config.d/*.conf" is found at the top of the "/etc/ssh/sshd_config" file:
$ cat << EOF | tee /etc/ssh/sshd_config.d/pubkey.conf
PubkeyAuthentication yes
EOF
Restart the SSH daemon for the settings to take effect:
$ systemctl restart sshd.service
Note: If the system administrator (SA) demonstrates the use of an approved alternate multifactor authentication method, this requirement is Not Applicable.
Verify that AlmaLinux OS 9 SSH daemon accepts public key encryption with the following command:
$ sshd -T | grep -i pubkeyauthentication
pubkeyauthentication yes
If "PubkeyAuthentication" is set to no, or the line is missing, this is a finding.