18.4. Configure the /etc/cron.daily/tripwire.verify script

The tripwire.verify file is a small script executed by the crond program of your server each day to scan your hard disk for possible changed files or directories and mail the results to the system administrator. This script will automate the procedure of integrity checking for you. If you intend to automate this task, follow the simple steps below.

  1. Create the tripwire.verify script file, touch /etc/cron.daily/tripwire.verify and add in this script:
    
          #!/bin/sh
              /usr/sbin/tripwire -loosedir -q | (cat <<EOF
              This is an automated report of possible file integrity changes, generated by
              the Tripwire integrity checker. To tell Tripwire that a file or entire
              directory tree is valid, as root run:
    
              /usr/sbin/tripwire -update [pathname|entry]
    
              If you wish to enter an interactive integrity checking and verification
              session, as root run:
    
              /usr/sbin/tripwire -interactive
    
              Changed files/directories include:
              EOF
              cat
              ) | /bin/mail -s "File integrity report" root
              

  2. Now, make this script executable and change its mode to be 0700 with the following command:
    
          [root@deep] /# chmod 700  /etc/cron.daily/tripwire.verify
              

18.4.1. Security Issue

It is recommended for better security that the database tw.db_[hostname] file of Tripwire be moved someplace e.g. floppy, where it cannot be modified. This is important because data from Tripwire is only as trustworthy as its database. It is also recommend that you make a hardcopy printout of the database contents right away. In the event that you become suspicious of the integrity of the database, you will be able to manually compare information against this hardcopy.

For more details, Further documentation, there are several man pages you can read:

siggen(8)

- signature generation routine for Tripwire

tripwire(8)

- a file integrity checker for UNIX systems

tw.config(5)

- configuration file for Tripwire

The commands listed in the next section are some that we use often in regular use, but many more exist. Check the man pages for more details.