IDS mailing list archives
Re: Obfuscated web pages
From: "Arian J. Evans" <arian () anachronic com>
Date: Thu, 14 Feb 2008 15:50:25 -0800
I believe the question was pretty clear, and so is the answer: + No -- today's networking products do not solve for this problem space. (Problem == client side payloads obfuscated to be later de-obfuscated and executed utilizing some scripting foo) Far too much performance overhead, for one. Real world deployment logistics limit inspection abilities in most scenarios, especially with encryption to meet regulations in play. Heck, some of the IPS on the market today don't do full bi-directional stream reassembly by default for speed reasons, let alone full HTTP decoding. Emulating some DOM assembly from the XHTML/ECMAscript isn't possible today. WAFs (web application firewalls) can barely keep up with this, and that's all they do. So, a "trustworthy network IPS" doesn't solve, for this (or other webappsec issue). An endpoint IPS might. I have limited experiences with these (they won't, obviously, solve for the webappsec issues leading to the planting and distribution of said obfuscated hostile code). A "locked down browser"? Where do I get one of those? The DOM-proxy thing is technically feasible, sure. However with the advent of rich media and other web 2.0 stuffs both the technology and the performance overhead of this problem is getting much harder, much faster than the feasibility of an inline DOM-based parser. I like your comment about yesterday's news; if things don't improve I too expect in the next few years we'll see some changes to the browser model sooner than we will see inline-browser-emulation-for-security solutions. Not that someone won't try it. ciao -- Arian Evans software security stuff On Thu, Feb 14, 2008 at 1:18 PM, Mike Barkett <mbarkett () us checkpoint com> wrote:
You're really talking about the difference between client-based protections and server-based protections. Let's not throw the baby out with the bathwater; network IDS/IPS does much more than just "AV style malware signatures for malicious web server issues." Most of today's IPS products can quite deftly clean out a vast array of types of malicious activity, whether automated or not, across a bevy of network protocols, not just web. Regarding inline JS inspection, I've said it before and I still believe that one day there will be a full DOM proxy product that is capable of running inline. Yes, its speeds will lag other network devices, and yes, browser attacks will probably be yesterday's news by then anyway, but it would be foolish to suggest that it is theoretically impossible to do. In the meantime, if you have embraced defense-in-depth and gotten yourself a trustworthy network IPS, a thorough endpoint solution, and you use only locked down browsers, then you'll be ok. -MAB -- Michael A Barkett, CISSP IPS Security Engineering Director Check Point Software Technologies +1.240.632.9000 Fax: +1.240.747.3512 > -----Original Message----- > > > Are any current network based IDS/P systems able to unwind > obfuscated web script to examine the final javascript product? > It would seem they would have to have a javascript engine to > do so and issues with reassembly, iterations, and delays > would preclude them from doing it inline. > > Without this capability, it would seem that network based > IDS/IPS is destined to digress to AV style malware > signatures for malicious web server issues and that the only > reliable place to do IDS/P would be on the host. > > We've been seeing more and more obfuscated web script and > according to a recently released IBM report, the majority > of exploits are taking this path. > > http://www.iss.net/x-force_report_images/2008/index.html > > Thoughts? > > -- > Gary Flynn > Security Engineer > James Madison University > www.jmu.edu/computing/security
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Current thread:
- Re: Obfuscated web pages, (continued)
- Re: Obfuscated web pages Gary Flynn (Feb 14)
- Re: Obfuscated web pages Stefano Zanero (Feb 19)
- Re: Obfuscated web pages Gary Flynn (Feb 14)
- Re: Obfuscated web pages Arian J. Evans (Feb 14)
- Re: Obfuscated web pages Mike Lococo (Feb 14)
- RE: Obfuscated web pages Mike Barkett (Feb 15)
- Re: Obfuscated web pages Ivan Arce (Feb 21)
- RE: Obfuscated web pages Mike Barkett (Feb 25)
- Re: Obfuscated web pages Ivan Arce (Feb 29)
- RE: Obfuscated web pages Mike Barkett (Feb 15)
- Re: Obfuscated web pages Arian J. Evans (Feb 15)
- RE: Obfuscated web pages Mike Barkett (Feb 15)
- Re: Obfuscated web pages Ivan Arce (Feb 21)
- Re: Obfuscated web pages Dustin D. Trammell (Feb 21)