nabou is a Perl script which can be used to monitor changes to your system. It provides file integrity checking, and can also watch crontabs, suid files and user accounts for changes. It stores all data in standard dbm databases.
You can download it from the following link: https://packetstormsecurity.com/files/download/34197/nabou-2.4.tar.gz
Source: https://packetstormsecurity.com/files/34197/nabou-2.4.tar.gz.html