Novell SuSe Linux LibTIFF Heap Overflow Vulnerability

iDEFENSE Security Advisory 10.22.04
www.idefense.com/application/poi/display?id=154&type=vulnerabilities
October 22, 2004

I. BACKGROUND

libtiff provides support for using the Tag Image File Format (TIFF), a
widely used format for storing image data.

II. DESCRIPTION

An exploitable heap overflow in the handling of malformed tiff files has
been discovered in the latest version of libtiff when JPEG support has
been enabled.

The overflow occurs in the OJPEGVSetField() function of
libtiff/tif_ojpeg.c. During processing, it is assumed that more than 255
bytes will not be processed, however in certain cases it is possible to
cause up to 16 times that amount of data to be processed, thus causing
the overflow.

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.

IV. DETECTION

iDEFENSE has confirmed the existence of this vulnerability in version
3.6.1 of libtiff when compiled with optional OJPEG_SUPPORT. This option
is enabled by default under SuSE Linux 9.1 Personal and Suse Linux 9.1
Professional.

V. WORKAROUND

Only open files from trusted users. Alternatively, recompile libtiff
without the optional OJPEG_SUPPORT.

VI. VENDOR RESPONSE

This issue is addressed in SUSE-SA:2004:038

   http://www.suse.de/de/security/2004_38_libtiff.html

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
names CAN-2004-0929 to these issues. This is a candidate for inclusion
in the CVE list (http://cve.mitre.org), which standardizes names for
security problems.

VIII. DISCLOSURE TIMELINE

09/09/2004   Initial vendor notification
09/09/2004   Vendor response
10/22/2004   Coordinated public disclosure

IX. CREDIT

Andrei Nigmatulin is credited with this discovery.

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X. LEGAL NOTICES

Copyright © 2004 iDEFENSE, Inc.

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