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Message-ID: <3F3ACD7E.8080201@immunix.com>
Date: Wed, 13 Aug 2003 16:45:02 -0700
From: Crispin Cowan <crispin@...unix.com>
To: "BUGTRAQ@...URITYFOCUS.COM" <BUGTRAQ@...URITYFOCUS.COM>,
secpapers@...urityfocus.com
Subject: PointGuard: It's not the Size of the Buffer, it's the Address of
the Pointer
This seems topical to today's discussion of buffer overflow defenses:
"PointGuard: Protecting Pointers From Buffer Overflow
Vulnerabilities". Crispin Cowan, Steve Beattie, John Johansen and
Perry Wagle. To appear at the 12^th USENIX Security Symposium
<http://www.usenix.org/events/sec03/>, Washington DC, August 4-8,
2003. Paper
<http://immunix.com/%7Ecrispin/pointguard_usenix_security2003.pdf>
and Talk
<http://immunix.com/%7Ecrispin/pointguard_usenix_security2003.ppt>.
PointGuard^TM : Protecting Pointers From Buffer Overflow Vulnerabilities
Crispin Cowan, Steve Beattie, John Johansen and Perry Wagle
Immunix, Inc.
Despite numerous security technologies crafted to resist buffer
overflow vulnerabilities, buffer overflows continue to be the
dominant form of software security vulnerability. This is because
most buffer overflow defenses provide only partial coverage, and the
attacks have adapted to exploit problems that are not well-defended,
such as heap overflows. This paper presents PointGuard, a compiler
technique to defend against most kinds of buffer overflows by
encrypting pointers when stored in memory, and decrypting them only
when loaded into CPU registers. We describe the PointGuard
implementation, show that PointGuard s overhead is low when
protecting real security-sensitive applications such as OpenSSL, and
show that PointGuard is effective in defending against buffer
overflow vulnerabilities that are not blocked by previous defenses.
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 Pointer
Crispin
--
Crispin Cowan, Ph.D. http://immunix.com/~crispin/
Chief Scientist, Immunix http://immunix.com
http://www.immunix.com/shop/
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