IDS mailing list archives

Re: Intrusion Detection Evaluation Datasets


From: Stefano Zanero <zanero () elet polimi it>
Date: Thu, 19 Mar 2009 19:47:57 +0100

Stuart Staniford wrote:

The original example was artificial, but the issue is very real.

Stuart, we are deviating from the original issue

A common obfuscation technique in javascript (more common a year or
two ago) is to have something like:
[...]
A simple string matching signature mechanism is useless here (you can
alert on things like "eval(unescape(" and some IDS's do, but you will false
positive like crazy as legitimate pages also use the idiom).

Really, you're pushing on an open door here. My whole research life has
been dedicated to anomaly detection, and I completely agree on simple
pattern matching being useless against such attacks and being far from
complete.

I just didn't agree on the specific example raised by Damiano, as I
don't see it happening anywhere in a real attack. Your example is much
more compelling (and you'll find similar ones in all of my
presentations, as well as Damiano's, I'm sure ;-)

SZ



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