Protecting Linux against automated attackers (Linux.com)
As many systems administrators will tell you, attacks from automated login scripts specifically targeting common account names with weak passwords have become a substantial threat to system security, especially via SSH (a popular program that allows remote users to log in to a Linux computer and execute commands locally). Here are some common-sense rules to follow that can greatly improve security, as well as several scripts to cut down on the computing resources wasted by these attacks."