0

TL;DR:

Question: how do I configure Tripwire to watch EVERYTHING that is below a certain path? My current config seems to only be looking at certain files / directories in a given path instead of everything.

Background / Full story:

I've recently installed Tripwire on a server that had some vulnerable PHP code. I added a rule called "Websites" that includes a number of sites that are run from the server (snippet below).

 # Rulset for websites
 (
   rulename = "Websites",
   severity = $(SIG_HI),
   emailto = "webmaster@hackedsite.com"
 )
 {
   /home/foouser1/www/ -> $(SEC_CRIT) (recurse = 1);
   /home/foouser2/www/ -> $(SEC_CRIT) (recurse = 1);
   /home/foouser3/www/ -> $(SEC_CRIT) (recurse = 1);
   /home/foouser4/www/ -> $(SEC_CRIT) (recurse = 1);
   /home/foouser5/www/ -> $(SEC_CRIT) (recurse = 1);
   /home/foouser6/www/ -> $(SEC_CRIT) (recurse = 1);
   /home/foouser7/www/ -> $(SEC_CRIT) (recurse = 1);
   /home/foouser8/www/ -> $(SEC_CRIT) (recurse = 1);
   /home/foouser9/www/ -> $(SEC_CRIT) (recurse = 1);
   /home/foouser10/www/ -> $(SEC_CRIT) (recurse = 1);
   /home/foouser11/www/ -> $(SEC_CRIT) (recurse = 1);
   /home/foouser12/www/ -> $(SEC_CRIT) (recurse = 1);
 }

I then updated the policy using:

/usr/sbin/twadmin --create-polfile -S site.key /etc/tripwire/twpol.txt

I entered my site key as expected, and the policy was updated without error.

When I run a check, there are no errors and no violations.

Then, to test it, I added an extra space to one of the files (/home/foouser1/www/foo/bar/js/script.js), which had previously (and repeatedly) been compromised. This should trigger a violation.

Re-running the check (tripwire --check -R Websites -v) shows several issues:

  1. Tripwire was ignoring the file, even thought it is below the declared file path /home/foouser1/www.
  2. It scans a bunch of files that are in /home/foouser1/www, but not all of them.

Finally, when I compare the directory contents of /home/foouser1/www to the number of files scanned by tripwire, there is a huge difference.

find /home/foouser1/www/ -type f -print | wc -l shows me there are 3,000+ files in that directory that should be watched by tripwire.

find /home/foouser1/www/ -type d -print | wc -l shows me there are 192 sub directories in that directory that should be watched by tripwire.

Tripwire reports that it only looked at 192 objects.

0

Turns out, that (recurse=1) is not needed. Recursive checking of files and subdirectories is on by default. But, in order to capture miniscule changes (single-byte changes, for example) you need to check the hash of the file (SHA is preferred). So, you can use the following variable as mask:

SEC_HACK_DETECT = $(IgnoreNone)-a ; # Files that should not change

Between these two changes, Tripwire then works as expected.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.