What Should You Immunize - Novell APPARMOR Admin Manual

How To Immunize With Novell AppArmor
Chapter 3 What Should You Immunize?
Novell AppArmor quarantines programs to protect the rest of the sys-
tem from being damaged by a compromised process. Thus programs
that need profiling are those that mediate privilege. For example,
sometimes a program has access to resources that the person using
the program does not have, which is true for the following types of pro-
grams:
• SetUID Programs: Programs that are setuid or setgid run as
the user or group that owns the program file, rather than the usual
case of running as the user and group of the person invoking the
program. For instructions on using Novell AppArmor for this type of
program, refer to " Immunizing SetUID Programs" o n p a g e1 2 .
• cron jobs: Programs that will be run periodically by cron. Such pro-
grams read input from a variety of sources, and may run with spe-
cial privileges, sometimes with as much as root privilege, e.g. cron
runs /usr/bin/updatedb daily to keep the slocate database up to
date, with sufficient privilege to read the name of every file in the
system. For instructions on using Novell AppArmor for this type of
program, refer to " Immunizing Cron Jobs" o n p a g e1 2 .
• Web Applications: Programs that can be invoked through a web
browser, including CGI PERL scripts, PHP pages, and more com-
plex web applications. For instructions on using Novell AppArmor
for this type of program, refer to " Immunizing Web Applications" o n
page 12.
• Network Agents: Programs (servers and clients) that have open
network ports. User clients such as mail clients and web browsers,
surprisingly, mediate privilege. These programs run with the privi-
l e g e t o w r i t e t o t h e u s e r ' s h o me d i r e c t o r i e s , a n d p r o c e s s i n p u t f r o m
potentially hostile remote sources, such as hostile web sites and e-
mailed malicious code. For instructions on using Novell AppArmor
for this type of program, refer to " Immunizing Network Agents" o n
page 14.
Conversely, unprivileged programs do not need to be profiled. For
instance, a shell script might invoke the cp program to copy a file.
Since cp does not have its own profile, it inherits the profile of the
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