From customerservice@idefense.com Mon Dec 13 16:26:01 2004 From: customer service mailbox To: bugtraq@securityfocus.com, vulnwatch@vulnwatch.org Date: Mon, 13 Dec 2004 13:30:57 -0500 Subject: iDEFENSE Security Advisory 12.13.04 - Multiple Vendor xzgv PRF Parsing Integer Overflow Vulnerability Multiple Vendor xzgv PRF Parsing Integer Overflow Vulnerability iDEFENSE Security Advisory 12.13.04 http://www.idefense.com/application/poi/display?id=160&type=vulnerabilit ies December 13, 2004 I. BACKGROUND xzgv is a picture viewer for X, with a thumbnail-based file selector. It uses GTK+ and Imlib 1.x. Most file formats are supported, and the thumbnails used are compatible with xv, zgv and the Gimp. II. DESCRIPTION Remote exploitation of an integer overflow vulnerability in various vendors' implementations of the read_prf_file method in the xzgv program could allow for arbitrary code execution. The vulnerability specifically exists due to an integer overflow while allocating memory for an image file. The vulnerable code is as follows: xzgv-0.8/src/readprf.c: if((*theimageptr=malloc(width*height*3))==NULL) [...] The values width and height are integers that are ultimately supplied by the image file. With certain values for height and width set in an image file, not enough memory is allocated due to an integer overflow. The underallocated memory is later written to, causing heap corruption and possible arbitrary code execution with the privileges of the user viewing the image file. III. ANALYSIS Exploitation allows attackers to gain the privileges of the user viewing the image file. If a user can be convinced to view a malicious file, this vulnerability can be exploited remotely. IV. DETECTION The following vendors have confirmed the availability of susceptible xzgv packages within their respective operating system distributions: SuSE Debian Gentoo FreeBSD V. WORKAROUND Only accept image files from trusted sources. Use a different image viewer program to view untrusted images. VI. VENDOR RESPONSE The vulnerability has been addressed in the following patch: http://rus.members.beeb.net/xzgv-0.8-integer-overflow-fix.diff VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CAN-2004-0994 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org), which standardizes names for security problems. VIII. DISCLOSURE TIMELINE 11/05/2004 Initial vendor notification 12/10/2004 Secondary vendor notification 12/10/2004 Initial vendor response 12/13/2004 Coordinated public disclosure IX. CREDIT Infamous41md is credited with this discovery. Get paid for vulnerability research http://www.idefense.com/poi/teams/vcp.jsp X. LEGAL NOTICES Copyright (c) 2004 iDEFENSE, Inc. Permission is granted for the redistribution of this alert electronically. It may not be edited in any way without the express written consent of iDEFENSE. If you wish to reprint the whole or any part of this alert in any other medium other than electronically, please email customerservice@idefense.com for permission. Disclaimer: The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information.