First post to the forum… hope this is the appropriate forum for this type of question… if not please advise -onto my question…

I have researched the various File Integrity Detection Systems, (tripwire, samhain, aide, fcheck, osiris, integrit, etc…) and have a good idea of their functionality. Additionally, I have briefed unSpawn’s Security references – great info that is a wealth of info, thanks!

The question that I have not been able to find the answer to is, what are the con’s versus pro’s of these products? I know each one has their market nitch, etc… what I’m looking for is a general overview of why one would or wouldn’t choose to use such a product. Plenty of pro’s (and sales pitches) as to why it is good but there also has to be some cons to such a product, (aside from configuration). Can anyone fill in this blank for me?

Thanks in advance -

Main pro: you know when files are changed.
Main con: it requires time/space to calculate and store the results.

Thanks for the reply....

Yea, tools are only as good as the user.... I was thinking that it might serve a dual purpose.

1. For system rebuilds / security...
2. For engineering other products onto the system. Could do a "snapshot" of a before and after on a "mirrored" test system to see exactly what files would be added. Therefore tracking space, etc...

In anyones experiences, are there any added vulnerabilities to the system by adding this tool?

Any other cons?

In anyones experiences, are there any added vulnerabilities to the system by adding this tool?
Depends on what your run and how you run it, but AFAIK there are no vulns that aren't part of regular sysadm stuff. I've only ran Integrit, Osiris, Samhain, tripwire and Aide and I've used Aide for years now. For example if you run a full setup of say Samhain, you'll want the LKM loaded, which (temporarily: minimally see "lcap") opens up a hole for loading LKM's.


Any other cons?
Again, AFAIK, none or it should be post-upgrade fall-out if you didn't run a check-and-update immediately after. It also takes a bit time to tune the conf setup to what purpose box it runs on. Say you have a ro-mounted /usr or something protected with extended attributes, then you could get away with regularly checking for instance /tmp, /var/tmp, /etc etc, etc and run one separate check for /usr on for example a weekly basis.

Just to be clear, this doesn't mean that having no LKM support prevents someone from tampering your running kernel (through /dev/kmem for example)? For this you would need to patch your kernel. with lids for example. Or is there a linux capability for preventing access to /dev/kmem?

I run samhain from another machine and mount a share to scan the files. I also keep the signature off the server to check (not because they can be modified since they are signed, only so that nobody sees that samhain is there). Thats high security, maybe too paranoid..

Main cons for me: you have a lot of things to read if its not a production server or your filters are not well set, I have removed it from my desktop pc for example..

Just to be clear, this doesn't mean that having no LKM support prevents someone from tampering your running kernel (through /dev/kmem for example)?
Disabling LKM support closes off only one of five holes.


Or is there a linux capability for preventing access to /dev/kmem?
That's CAP_SYS_RAWIO. Before you run lcap to disable that you will want to check breakage like X11/Xorg on desktops.

Oh I had missed this one. No need for external patch. As I said, I won't do it on a desktop ; and on my server, I don't run X at all.

Thanks a lot.

There's this comparation that's somewhat old, but you may find out which features are mandatory for an FIC scanner.

http://la-samhna.de/library/scanners.html