
			    What is TIGER?

     TIGER, or the 'tiger' scripts, is a set of Bourne shell scripts,
C programs and data files which are used to perform a security audit
of UNIX systems.  It is designed to hopefully be easy to use, easy to
understand and easy to enhance.  Currently support for SunOS 4.x and
SunOS 5.x is the best, followed by NeXT 3.x.  Other systems for which
(at least partial) configuration files are provided are IRIX 4.x, AIX
3.x, UNICOS 6.x, Linux 0.99.x and HP/UX.  These configurations are not
tested as thoroughly as the SunOS and NeXT configurations, and in some
cases, may barely work.  For other systems, a "best effort" check will
be performed.

     TIGER has one primary goal: report ways 'root' can be
compromised.  While checks are performed for other purposes, most of
the checks are directed at this goal.  The primary assumption made is
that any uid other than 0 can be obtained (if you aren't as paranoid
as I am, you could tell it to trust, oh, say 'bin'... but don't!) and
that *any* gid can be obtained by unauthorized persons.

     What does it do to do this?  Paths into 'root' (cron, inetd,
setuid executables, PATH, etc, etc) are all checked to see if anyone
other than 'root' can alter that path.  Any such instances are
flagged.  (In reality, paths into other accounts are checked for
vulnerability, but 'root' receives special attention).

A brief run down of some of the checks (not complete):

o  cron entries are checked
o  mail aliases are checked
o  NFS exports are checked
o  inetd entries are checked
o  PATH variables are checked
o  .rhosts & .netrc files are checked
o  Specific file & directory access permissions are checked
o  File system scans locate unusual files
o  Digital signatures are used to detect alterations to key
   binaries (signatures are generated from CD-ROM) and also to
   report binaries for which (updated) security patches exist.
o  Pathnames embedded in any files reported by most of the other
   checks are checked.

    The amount of time required to execute TIGER varies on system size
and the TIGER configuration settings.  On a SparcStation LX with 1GB
of disk, less than 20 users, and a strenuous TIGER configuration, it
takes about 90 minutes.  A less strenuous TIGER configuration can run
in about 25 minutes on the same machine configuration.  The bulk of
this time is used by the file system scans and check of embedded
pathnames.  On systems with a large number of users, other checks will
dominate.
