Re: [gentoo-security] tripwire-ish portage scanner

[Andrea Barisani]

On Thu, Mar 25, 2004 at 09:16:05PM +0100, Michel Wilson wrote:
> On Thu, Mar 25, 2004 at 02:03:45PM -0600, Andrew Gaffney wrote:
> > Tom Hosiawa wrote:
> > >What about qpkq being compromised itself. As I understand it, in
> > >tripwire, cryptographic keys are used for the policy file.
> > >
> > >Couldn't an attacker mess around with which files qpkq scans?
> >
> > That's another good reason for a customer portage-integrated solution.
> >
> Oh yeah, that's a little 'detail' I forgot, yes :P
> The integrity scanner itself can indeed be compromised. There isn't much
> we can do about this, it's a chicken-and-egg problem. One solution would
> be a read-only medium to store the scanner on, or a copy of gpg + the
> signature of the scanner. But that is kind of problematic. And what
> about an attacker that installs a rootkit so that the scanned files
> appear to be intact when opened by the scanner, but not when opened by
> the kernel?
> To make a long story short, one can never be sure. My opinion is that
> something along the lines of Tripwire is secure enough in most cases.
> Tripwire can also be fooled by replacing the binary itself. If the
> attacker does it right, no-one will notice. I.e. same file size, only skip
> scanning files that are compromised so that there will still be false
> alerts upon upgrades, etc.
>
> Michel Wilson.

I suggest that you look at samhain:

http://la-samhna.de/samhain

It's an excellent file integrity and host-based intrusion detection system
with advanced features that solves the "chicken-and-egg" problem along with
other cool gizmos :).


Bye

-- 
Andrea Barisani <lcars@g.o>                            .*.
Gentoo Linux Infrastructure Developer                          V
                                                             (   )
GPG-Key 0x864C9B9E http://dev.gentoo.org/~lcars/pubkey.asc   (   )
    0A76 074A 02CD E989 CE7F AC3F DA47 578E 864C 9B9E        ^^_^^

--
gentoo-security@g.o mailing list