IDS mailing list archives
Re: IDS\IPS that can handle one Gig
From: Mike Frantzen <frantzen () nfr com>
Date: Mon, 6 Jun 2005 10:26:52 -0400
Think about it from an architectural perspective - these devices have a single REGEX processor, and performance will degrade the more signatures you tell this processor to look for.
There are a plethora of multi-pattern regex algorithms that even with a ton of patterns will only walk the packet data once (not many times as most people would think). Shift-Or, Aho-Corasick and DFAs are the ones that immedietly jump to mind. IIRC they're all between O(n) and O(n+m) where 'n' is your data length and 'm' is your maximum pattern size. Notice that the algorimic complexities don't care about the number of signatures... There are other reasons not to design intrusion detection/prevention around pattern matching. But performance is certainly not one. The perfomanace nut in me wishes we at NFR could switch our product to pattern matching. Then I remember I'm a security guy. .mike frantzen@(nfr.com | cvs.openbsd.org | w4g.org) PGP: CC A4 E2 E8 0C F8 42 F0 BC 26 85 5B 6F 9E ED 28 -------------------------------------------------------------------------- Test Your IDS Is your IDS deployed correctly? Find out quickly and easily by testing it with real-world attacks from CORE IMPACT. Go to http://www.securityfocus.com/sponsor/CoreSecurity_focus-ids_040708 to learn more. --------------------------------------------------------------------------
Current thread:
- RE: IDS\IPS that can handle one Gig, (continued)
- RE: IDS\IPS that can handle one Gig Prashant Khandelwal (Jun 01)
- RE: IDS\IPS that can handle one Gig THolman (Jun 01)
- Re: IDS\IPS that can handle one Gig Peter Schawacker (Jun 01)
- RE: IDS\IPS that can handle one Gig Dave Hawkins (Jun 01)
- RE: IDS\IPS that can handle one Gig Palmer, Paul (ISSAtlanta) (Jun 04)
- RE: IDS\IPS that can handle one Gig THolman (Jun 04)
- Re: IDS\IPS that can handle one Gig Ed Gibbs (Jun 04)
- RE: IDS\IPS that can handle one Gig Chris Harrington (Jun 06)
- Re: IDS\IPS that can handle one Gig Nick Black (Jun 07)
- RE: IDS\IPS that can handle one Gig THolman (Jun 04)
- Re: IDS\IPS that can handle one Gig Mike Frantzen (Jun 06)
- Re: IDS\IPS that can handle one Gig Nick Black (Jun 07)
- Re: IDS\IPS that can handle one Gig Mike Frantzen (Jun 06)
- Re: IDS\IPS that can handle one Gig Ed Gibbs (Jun 06)
- IPS test criteria (was IDS\IPS that can handle one Gig) Bob Walder (Jun 07)
- RE: IDS\IPS that can handle one Gig Gary Halleen (Jun 06)
- RE: IDS\IPS that can handle one Gig Hovis, Chris (Jun 07)
- RE: IDS\IPS that can handle one Gig THolman (Jun 07)
- RE: IDS\IPS that can handle one Gig Edward Sohn (Jun 08)
- RE: IDS\IPS that can handle one Gig Barrett G . Lyon (Jun 08)
- RE: IDS\IPS that can handle one Gig Palmer, Paul (ISSAtlanta) (Jun 08)
- RE: IDS\IPS that can handle one Gig Andrew Plato (Jun 10)
(Thread continues...)