Description:

AIDE (Advanced Intrusion Detection Environment) is a free replacement for
Tripwire. It does the same things as the semi-free Tripwire and more.

There are other free replacements available so why build a new one? All the
other replacements do not achieve the level of Tripwire. And I wanted a
program that would exceed the limitations of Tripwire.

The idea is that for an intruder to get in, certain files on the system must
change - configuration files, for example. And once an intruder is in, in
order to do much useful, the intruder must gain root access - something else
that requires changing files. aide ensures that you (root) can be notified of
ANY changes to a configurable list of properties (modification date, size,
various hash-values) of a configurable list files.

Aide should be installed right after the OS installation, and before
you have connected your system to a network (i.e., before any
possibility exists that someone could alter files on your system).