Bugtraq mailing list archives
Re: PointGuard: It's not the Size of the Buffer, it's the Address of the Pointer
From: Crispin Cowan <crispin () immunix com>
Date: Fri, 15 Aug 2003 11:00:04 -0700
Florian Weimer wrote:
Please address technical commentary to the paper (which addresses this point) and not to the cute tag line.Crispin Cowan <crispin () immunix com> writes:Thanks to Snax and the Shmoo for a better tag line: It's not the Size of the Buffer, it's the Address of the PointerThis is not true. There are buffer overflow exploits which do not modify pointers, but other objects. The most prominent example is probably the "c c c c c..." exploit for the Solaris /bin/login vulnerability.
WRT this point: correct, PointGuard does not stop all buffer overflows. IMHO it *nearly* stops all shell code. To bypass PointGuard, you have to corrupt the logic of the program itself to get its own code to do what you want; you can't readily generate a jump to arbitrary code.
Caveat: I can't prove the above, and someone may generate a bypass. But I don't know of one.
Crispin -- Crispin Cowan, Ph.D. http://immunix.com/~crispin/ Chief Scientist, Immunix http://immunix.com http://www.immunix.com/shop/
Current thread:
- PointGuard: It's not the Size of the Buffer, it's the Address of the Pointer Crispin Cowan (Aug 14)
- Re: PointGuard: It's not the Size of the Buffer, it's the Address of the Pointer Florian Weimer (Aug 15)
- Re: PointGuard: It's not the Size of the Buffer, it's the Address of the Pointer Crispin Cowan (Aug 15)
- Message not available
- Re: PointGuard: It's not the Size of the Buffer, it's the Address of the Pointer Crispin Cowan (Aug 15)
- Re: PointGuard: It's not the Size of the Buffer, it's the Address of the Pointer Crispin Cowan (Aug 15)
- Re: PointGuard: It's not the Size of the Buffer, it's the Address of the Pointer Florian Weimer (Aug 15)