V-215402

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, non-organization-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.

Check Content

Check the SSH daemon configuration for allowed ciphers by running the following command: 
# grep -i ciphers /etc/ssh/sshd_config | grep -v '^#' 

The above command should yield the following output:
Ciphers aes128-ctr,aes192-ctr,aes256-ctr

If any of the following conditions are true, this is a finding.
1. No line is returned (default ciphers);
2. The returned ciphers list contains any cipher not starting with aes;
3. The returned ciphers list contains any cipher ending with cbc.