Bugtraq mailing list archives
Re: iDEFENSE Security Advisory 12.21.04: libtiff STRIPOFFSETS Integer Overflow Vulnerability
From: "Dmitry V. Levin" <ldv () altlinux org>
Date: Wed, 22 Dec 2004 14:45:45 +0300
Hi, On Tue, Dec 21, 2004 at 05:09:30PM -0500, customer service mailbox wrote:
libtiff STRIPOFFSETS Integer Overflow Vulnerability iDEFENSE Security Advisory 12.21.04 www.idefense.com/application/poi/display?id=173&type=vulnerabilities December 21, 2004 I. BACKGROUND libtiff provides support for the Tag Image File Format (TIFF), a widely used format for storing image data. More information is available at the following site: http://www.remotesensing.org/libtiff/ II. DESCRIPTION Remote exploitation of an integer overflow in libtiff may allow for the execution of arbitrary code. The overflow occurs in the parsing of TIFF files set with the STRIPOFFSETS flag in libtiff/tif_dirread.c. In the TIFFFetchStripThing() function, the number of strips (nstrips) is used directly in a CheckMalloc() routine without sanity checking. The call ultimately boils down to: malloc(user_supplied_int*size(int32)); When supplied 0x40000000 as the user supplied integer, malloc is called with a length argument of 0. This has the effect of returning the smallest possible malloc chunk. A user controlled buffer is subsequently copied to that small heap buffer, causing a heap overflow. When exploited, it is possible to overwrite heap structures and seize control of execution. III. ANALYSIS An attacker can exploit the above-described vulnerability to execute arbitrary code under the permissions of the target user. Successful exploitation requires that the attacker convince the end user to open the malicious TIFF file using an application linked with a vulnerable version of libtiff. Exploitation of this vulnerability against a remote target is difficult because of the precision required in the attack. IV. DETECTION iDEFENSE has confirmed this vulnerability in libtiff 3.6.1. Changes were introduced in libtiff 3.7.0 that had the effect of fixing this vulnerability. The following vendors provide susceptible libtiff packages within their respective operating system distributions: - Gentoo Linux - Fedora Linux - RedHat Linux - SuSE Linux - Debian Linux V. WORKAROUND Only open TIFF files from trusted users. VI. VENDOR RESPONSE This issue is addressed in libtiff 3.7.0 and 3.7.1. VII. CVE INFORMATION A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not been assigned yet.
I believe this issue is subset of CAN-2004-0886 which was fixed in the middle of October. -- ldv
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Current thread:
- iDEFENSE Security Advisory 12.21.04: libtiff STRIPOFFSETS Integer Overflow Vulnerability customer service mailbox (Dec 21)
- Re: iDEFENSE Security Advisory 12.21.04: libtiff STRIPOFFSETS Integer Overflow Vulnerability Dmitry V. Levin (Dec 22)
- Re: iDEFENSE Security Advisory 12.21.04: libtiff STRIPOFFSETS Integer Overflow Vulnerability Moritz Muehlenhoff (Dec 23)
- Re: iDEFENSE Security Advisory 12.21.04: libtiff STRIPOFFSETS Integer Overflow Vulnerability Marcus Meissner (Dec 28)