Re: Microsoft GhostBuster Opionions

[Dave King <davefd () davewking com>]

bkfsec wrote:

> Valdis.Kletnieks () vt edu wrote:
>
> > On Thu, 17 Mar 2005 11:28:55 MST, Dave King said:
> >
> >  
> >
> > >    Also, this is not just like tripwire.  If the kernel is 
> > > compromised and reporting false data to tripwire then tripwire can 
> > > run along merrily thinking every thing's great.  This is why booting 
> > > to a trusted kernel is important for the process.  Exploiting 
> > > Software by Hoglund and McGraw has a discussion on these types of 
> > > rootkits.  Tripwire, however does great at detecting other sorts of 
> > > intrusions.
> > >   
> >
> >
> > Actually, the "prior art" *is* tripwire.  If you run tripwire on the 
> > live
> > system, then run it while booted from a CD, and they produce different
> > results, you have a problem.
> >
> > And that's what they're doing by doing a 'dir /a /s' on the live system,
> > then booting the Windows PE CD, and looking for differences....
> >  
> >
> >  
>
> In fact, it's even more simple than that.  Tripwire is far more 
> complex than a 'dir /a /s' and comparing the file differences.
>
> A 'dir /a /s' is more comparible to a 'tree -afi' (I believe these are 
> the right command line switches - this was entered on memory) on Unix 
> systems with the tree binary installed.  All you need to do is boot 
> from another media, rinse, repeat, and run a diff on the two files.
>
> This would place the prior art even further back in time.  And dare I 
> say that the output of tree would even be more useful than the dir 
> output, not to mention the fact that the tripwire check is just in 
> another league entirely.  (Meaning far far far more useful output.)
>
>             -Barry

   That's true, I meant Tripwire no disrespect.  I used tripwire for 
several years, and since have used Samhain and Osiris.  All or which are 
great tools for checking the integrety of the files.  A couple of things 
to think about though.  First 'dir /a /s' can get through an entire 
drive much faster than these other tools and sometimes speed is 
important.  Checking the entire drive will almost always be overkill, 
but that's just what the original paper talked about doing which is why  
I mentioned it.  Second, as far as I can tell Tripwire for Windows isn't 
free like it is for Linux.  While this shouldn't be the only reason to 
make a decission not to use a product it's not a bad idea to look at 
other possibilities as well.  Osiris works on Windows and could possibly 
be used to check the file integrety.  Another option would be to use 
Microsoft's File Checksum Integrity Verifier utility 
http://support.microsoft.com/?kbid=841290 .  I have tried running 
Microsoft's tool on 25 GB of files and it took about 3 hours to check 
about 15,000 directories and 138,000 files.

   So while Tripwire is a great tool with many great features it seems 
that there are tools that can perform the tasks needed to do one scan 
for free.  It would also be very easy to build a small C++ program to 
make these hashes as well.

Thanks for the input,
Dave King
http://www.thesecure.net



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