Common

1. PubkeyAuthentication option contains “yes” as the default value.

2. Disable Root Login (PermitRootLogin)

3. Allow Only Specific Users or Groups (AllowUsers AllowGroups)

4. Deny Specific Users or Groups (DenyUsers DenyGroups)

5. Change SSHD Port Number (Port)

6. Change Login Grace Time (LoginGraceTime)

7. Restrict the Interface (IP Address) to Login (ListenAddress)

8. Disconnect SSH when no activity (ClientAliveInterval)

Find directory with 777 permission.

$find . -type d -perm 777

Check /var/log/secure , /var/log/messages and other log files of services running to see if there are any issues.

Change ssh ListenAddress /etc/ssh/sshd_config

#PermitRootLogin no

what are the seven fields in the /etc/passwd file

#username, UID, GID, comment, home directory, command