Check: SLEM-05-255045
SUSE Linux Enterprise Micro (SLEM) 5 STIG:
SLEM-05-255045
(in version v1 r1)
Title
SLEM 5 must implement DOD-approved encryption to protect the confidentiality of SSH remote connections. (Cat I impact)
Discussion
Without confidentiality protection mechanisms, unauthorized individuals may gain access to sensitive information via a remote access session. Remote access is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Encryption provides a means to secure the remote connection to prevent unauthorized access to the data traversing the remote access connection (e.g., RDP), thereby providing a degree of confidentiality. The encryption strength of a mechanism is selected based on the security categorization of the information. The system will attempt to use the first cipher presented by the client that matches the server list. Listing the values "strongest to weakest" is a method to ensure the use of the strongest cipher available to secure the SSH connection.
Check Content
Verify that SLEM 5 implements DOD-approved encryption to protect the confidentiality of SSH remote connections with the following command: > sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*ciphers' /etc/ssh/sshd_config:Ciphers aes256-ctr,aes192-ctr,aes128-ctr If any ciphers other than "aes256-ctr", "aes192-ctr", or "aes128-ctr" are listed, the order differs from the example above, the line is commented out, or the "Ciphers" keyword is missing, or conflicting results are returned, this is a finding.
Fix Text
Configure the SSH server to only implement FIPS 140-2/140-3 approved ciphers. Add or modify the following line in the "/etc/ssh/sshd_config" file: Ciphers aes256-ctr,aes192-ctr,aes128-ctr Restart the SSH daemon: > sudo systemctl restart sshd.service
Additional Identifiers
Rule ID: SV-261334r996467_rule
Vulnerability ID: V-261334
Group Title: SRG-OS-000033-GPOS-00014
Expert Comments
CCIs
| Number | Definition |
|---|---|
| CCI-000068 |
Implement cryptographic mechanisms to protect the confidentiality of remote access sessions. |
| CCI-000877 |
Employ strong authentication in the establishment of nonlocal maintenance and diagnostic sessions. |
| CCI-001453 |
Implement cryptographic mechanisms to protect the integrity of remote access sessions. |
| CCI-002890 |
Implement organization-defined cryptographic mechanisms to protect the integrity of nonlocal maintenance and diagnostic communications. |