Which of the following actions would BEST address the potential risks by the activity in the logs?

A security analyst receives an alert from the SIEM regarding unusual activity on an authorized public SSH jump server. To further investigate, the analyst pulls the event logs directly from /var/log/auth.log: graphic.ssh_auth_log.

Which of the following actions would BEST address the potential risks by the activity in the logs?
A . Alerting the misconfigured service account password
B . Modifying the AllowUsers configuration directive
C . Restricting external port 22 access
D . Implementing host-key preferences

Answer: C

Explanation:

Reference: https://www.rapid7.com/blog/post/2017/10/04/how-to-secure-ssh-server-using-port-knocking-on-ubuntu-linux/