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Message-Id: <20061222005808.2AA631D8F79@supertolla.itapac.net>
Date: Fri, 22 Dec 2006 01:58:19 +0100
From: "Michele Cicciotti" <mc@...msa.net>
To: <full-disclosure@...ts.grok.org.uk>
Cc: <bugtraq@...urityfocus.com>
Subject: RE: [Full-disclosure] Microsoft Windows XP/2003/Vista memory corruption 0day
> Holy mackerel! Instances of this bug date back to 1999!
Different bug. That appears to be a trivial exhaustion of CSRSS worker threads through indiscriminate calls to MessageBox+MB_SERVICE_NOTIFICATION, which causes a DoS as no threads are available to serve kernel-mode requests from win32k, stalling GUI processes. I have done my fair share of CSRSS reversing in my better days, and I'm pretty sure that in Windows 2000 and later, a dedicated thread is used for such notifications, not just any thread, any time. Easily verifiable with local net sends and Spy++. It wasn't a "bug" either, more like a serious design flaw that ignored a very basic Win32 mantra ("don't do GUI in a worker thread") - not at all like this double-free
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