Avamar: Remote SSH server is configured to use the Arcfour stream cipher

The security scanner reports the following problem: "Remote SSH server is configured to use the Arcfour stream cipher"

Note: Basic knowledge of Linux version of vi editor is required to complete the following steps. 

1. Log into the node as the admin user, then switch to root:

su -

Enter the root password when prompted.
2. Make a copy of /etc/ssh/sshd_config file

cp -p /etc/ssh/sshd_config /etc/ssh/x-sshd_config_`date -I`

3. Edit the /etc/ssh/sshd_config file 

vi /etc/ssh/sshd_config

4. Comment out the line starting with "Ciphers" (if exists) by inserting the # symbol at the beginning of line.
5. Insert the following line between the "Protocol 2" line and the "UseDNS no" line:

Ciphers aes128-ctr,aes192-ctr,aes256-ctr

6. Save the file and run a syntax check:

/usr/sbin/sshd -t

7. If the syntax check comes back clean, restart the SSH daemon:

service sshd restart

8. Use the "exit" command to return to an admin shell, then run the following command to confirm that arcfour is now disabled:

ssh -c arcfour localhost  'date'

Example of expected command output:
[/home/admin]=>ssh -c arcfour localhost  'date'
no matching cipher found: client arcfour server aes128-ctr,aes192-ctr,aes256-ctr

Once it is confirmed that arcfour is no longer in the cipher list, please re-run the security scan.