Hackers Beware

UNIX Fundamentals

Now that we have covered some common ways that UNIX systems are compromised, let’s cover some key fundamentals of UNIX. These concepts are needed not only to understand specific UNIX exploits, but to understand how to protect a site. The following are the areas that are covered:

• key commands

• file permissions

• inetd

• netstat

• tripwire

• TCP wrappers

• lsof

• suid

It is important to point out that some of these items listed are not part of the native UNIX operating system; they are add-on programs. Because the add-ons are integral to securing a UNIX system and are loaded on most UNIX systems, they are included in this section. Some of these programs, such as tripwire and TCP wrappers, help provide a defense in depth posture for securing a UNIX ...