5.2.21 Ensure SSH MaxStartups is configured

Information

The MaxStartups parameter specifies the maximum number of concurrent unauthenticated connections to the SSH daemon.

To protect a system from denial of service due to a large number of pending authentication connection attempts, use the rate limiting function of MaxStartups to protect availability of sshd logins and prevent overwhelming the daemon.

Solution

Edit the /etc/ssh/sshd_config file to set the parameter as follows:

maxstartups 10:30:60

See Also

https://workbench.cisecurity.org/files/3682