FreeBSD6 Unleashed

The Security Risks You Face

“Perfect security” is a myth; only superhuman effort can keep a system so completely buttoned up that no attack can ever get through. The next best thing, however, is to know which areas of your system are at greatest risk and how those risks can be combated.

Security risks for a network server can be grouped into three major categories:

• Root compromise— An attacker takes advantage of unencrypted transmissions or known programming weaknesses in server software (most commonly buffer overflows, or weaknesses in input boundary checking in server software) to gain super-user access to the system. He then installs tools of his own to conceal his presence from your system-monitoring tools (such as last and ps) and can steal ...