Snort mailing list archives

PCRE and normalized content


From: Paul Schmehl <pschmehl_lists () tx rr com>
Date: Wed, 13 Jan 2010 17:52:20 -0600

This string: %20%61%6E%64%20%31%3D%31
equals this string: ' and 1=1'
after normalization.  You can pick this up in a rule by using uricontent 
instead of content.  But what do you do about PCRE?  Is there a way to get PCRE 
to match against normalized content?  Or will it only match against 
non-normalized content?

I'm working on sql injection rules and using the following pcre: 
pcre:"/and\s(\d+)=\1/";

It works fine on 1=1 or 54=54, but fails on %31%3D%31, apparently because it's 
attempting to match against the non-normalized content.

-- 
Paul Schmehl, Senior Infosec Analyst
As if it wasn't already obvious, my opinions
are my own and not those of my employer.
*******************************************
"It is as useless to argue with those who have
renounced the use of reason as to administer
medication to the dead." Thomas Jefferson


------------------------------------------------------------------------------
Throughout its 18-year history, RSA Conference consistently attracts the
world's best and brightest in the field, creating opportunities for Conference
attendees to learn about information security's most important issues through
interactions with peers, luminaries and emerging and established companies.
http://p.sf.net/sfu/rsaconf-dev2dev
_______________________________________________
Snort-sigs mailing list
Snort-sigs () lists sourceforge net
https://lists.sourceforge.net/lists/listinfo/snort-sigs


Current thread: