Exploits and Attacks
The Internet today is riddled with programs designed to disable, destroy, or break into other systems. It is a system administrator's job to ward off these attacks and keep services available and data secure. The two most common types of attacks on a Unix system are exploits for privileged accounts, which use bugs in programs and poor configurations to gain unauthorized access to accounts, and denial-of-service attacks, which render services unusable.
In the sections that follow, you learn how some of the most damaging Unix system attacks occur, and some effective techniques for preventing them from invading your systems.
Many exploits are packaged by hackers into a convenient script that can be run by anyone ...