Ensure minimum SSH Encryption algorithm is set to aes128-cbc

How it is checked

Audit method: Manual review

This recommendation cannot be checked automatically. A scan lists it with these instructions when you pass --include-manual.

Run 'tmsh list sys sshd all-properties' and review the include statement: a 'Ciphers' line must restrict SSH to the organisation-approved ciphers (the CIS example starts the list with aes128-cbc, aes128-ctr, aes192-ctr, aes256-ctr). Note the CIS example also lists arcfour ciphers, which are weak; prefer CTR/GCM ciphers only.

How it is fixed

Fix method: Guidance or infrastructure patch

1-Log in to tmsh by typing the following command:tmsh 2-To modify the sshd configuration, type the following command to start the vi editor:edit /sys sshd all-properties 3-To change the list of ciphers, you can navigate to the line that starts with the include statement, and use the keyword Ciphers : include "Ciphers aes128-cbc,aes128-ctr,aes192-ctr,aes256- ctr,arcfour128,arcfour256,arcfour"