A pair of hackers (including a personal friend) have identified a flaw in the design of Windows Data Execution Protection (DEP/NX), which ordinarily protects the system against remote code execution and other exploits that involve the execution of data, on capable processors. This flaw, detailed in their article, allows a worm or other malicious program to remotely disable DEP via a buffer overflow procedure that does not inject code of its own (and is thus not prevented by DEP). This possibility is not due to a bug in Windows, but rather due to the design decision to allow programs (for compatibility purposes) to disable their own DEP. As such, it cannot be 'fixed' in the normal sense; however, some clever tricks of Windows coding can be used to thwart this attack.
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Thursday, January 05, 2006
I Have Scary Friends
Oh yeah, and did you know that NX/DEP (the feature that prevents execution of noncode - i.e. buffer overflows tactics - in Windows XP+) doesn't work? Just got this link from Skywing (one of my 'best' friends - that is, the ones I talk to the most), although it's back from October. Notice the names of the authors. After reading this, I submitted the following summary to Slashdot (we'll see if it actually gets accepted):