SP2's data execution protection cracked
Robert Lemos
CNET News.com
January 31, 2005, 09:30 GMT
A Russian security firm has published a paper detailing a major security flaw in Microsoft Service Pack Two for Windows XP, over a month after alerting Redmond to the flaw
A Russian security company claims it found a way to beat a security measure in Microsoft's Windows XP Service Pack 2.
The SP2 measure, known as Data Execution Protection, is intended to prevent would-be attackers from inserting rogue code into a PC's memory and tricking Windows into running the program. However, in a paper published on Friday, Moscow-based Positive Technologies said two minor mistakes in the implementation of the technology allow a knowledgeable programmer to sidestep the protection.
The company notified Microsoft of the problem on 22 December, but it apparently decided not to wait for the software giant to patch the flaws.
Neither Microsoft nor Positive Technologies immediately responded to requests for comment on Friday.
After several delays, Microsoft began rolling out SP2 in August of last year, at which time company chairman Bill Gates called the update "a significant step in delivering on our goal to help customers make their PCs better isolated and more resilient in the face of increasingly sophisticated attacks."
Problem
In October 2004 it was discovered by MaxPatrol team that it is possible to defeat Microsoft® Windows® XP SP2 Heap protection and Data Execution Prevention mechanism. As a result it is possible to implement:
Arbitrary memory region write access (smaller or equal to 1016 bytes)
1. Arbitrary code execution
2. DEP bypass.
Details are described in the article by experts
Solution
As a temporary security measure we've developed simple utility PTmsHORP, which allows restriction of lookaside list creation, governed by a special global flag.
Download PTmsHORP (21 Kb)
During the first execution this program shows the list of applications which already have this flag set. In order to activate this safety flag for other applications you just need to add the name of the executable file to the list. Any time you can review or modify the list of protected applications by running PTmsHORP again.
<font color="red">Warning. The flag, while enabled, may decrease the application performance.</font id="red">
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