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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2006.0902 -- [Linux] Sophos Antivirus CHM Chunk Name Length Memory Corruption and File Heap Overflow Vulnerabilities 11 December 2006 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Sophos Small business edition 4.06.1 (engine 2.34.3) Sophos Antivirus for Linux 4.03 (engine 4.05) Publisher: iDEFENSE Operating System: Linux variants Impact: Execute Arbitrary Code/Commands Denial of Service Access: Remote/Unauthenticated CVE Names: CVE-2006-5647 CVE-2006-5646 Original Bulletin: http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=452 http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=451 Comment: Note that this bulletin contains two iDefense advisories. - --------------------------BEGIN INCLUDED TEXT-------------------- Sophos Antivirus CHM Chunk Name Length Memory Corruption Vulnerability iDefense Security Advisory 12.08.06 http://labs.idefense.com/intelligence/vulnerabilities/ Dec 08, 2006 I. BACKGROUND Sophos AntiVirus offers protection from the latest Trojans, worms and Viruses. More information is available on the vendors site at: http://sophos.com/products/ II. DESCRIPTION Sophos AntiVirus Engine is vulnerable to a Memory Corruption vulnerability when scanning malformed CHM archives. This memory corruption vulnerability can be triggered when Sophos Antivirus engine scans a malformed CHM file which has a large name length specified in a CHM chunk header. III. ANALYSIS Malformed CHM files can lead to a Memory Corruption condition on the local machine. This memory corruption vulnerability could potentially result in arbitrary code execution. Files received as email attachments, uploaded via web forms or otherwise saved to disk may trigger this condition if auto scanning is enabled on the target machine. Archive scanning is disabled by default and must be specified in order for this vulnerability to trigger. IV. DETECTION iDefense has confirmed this vulnerability in the following Sophos Antivirus products: * Sophos Small business edition (Linux) Product version: 4.06.1 Engine version : 2.34.3 Previous versions of Sophos Antivirus are suspected vulnerable. Other Sophos Antivirus products may also be vulnerable. Windows versions of the Sophos Antivirus product do not appear to be vulnerable. V. WORKAROUND Disabling the option to scan within archives will prevent exploitation of this vulnerability. VI. VENDOR RESPONSE Sophos has addressed this problem with new versions of their products. See http://www.sophos.com/support/knowledgebase/article/7609.html for more information. VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2006-5647 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 09/28/2006 Initial vendor notification 10/02/2006 Initial vendor response 12/08/2006 Coordinated public disclosure IX. CREDIT This vulnerability was reported to iDefense by Damian Put <pucik@overflow.pl>. Get paid for vulnerability research http://labs.idefense.com/methodology/vulnerability/vcp.php Free tools, research and upcoming events http://labs.idefense.com/ X. LEGAL NOTICES Copyright © 2006 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 e-mail 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. ========================================================================== Sophos Antivirus CHM File Heap Overflow Vulnerability iDefense Security Advisory 12.08.06 http://labs.idefense.com/intelligence/vulnerabilities/ Dec 08, 2006 I. BACKGROUND Sophos AntiVirus offers protection from the latest Trojans, worms and Viruses. More information is available on the vendors site at: http://sophos.com/products/ II. DESCRIPTION Sophos AntiVirus Engine is vulnerable to a Heap Overflow attack when scanning malformed CHM archives. Specifically, if the CHM file has a Window_size of 0 set in a LZX decompression header then memory corruption will occur. III. ANALYSIS Malformed CHM files can lead to a heap overflow condition on the local machine. Files received as email attachments, uploaded via web forms or otherwise saved to disk may trigger this condition if auto scanning is enabled on the target machine. Archive scanning is disabled by default and must be specified in order for this vulnerability to trigger. IV. DETECTION iDefense has confirmed this vulnerability in the following Sophos Antivirus products: * Sophos Antivirus for Linux Product version: 4.03 Engine version : 4.05 Previous versions of Sophos Antivirus are suspected vulnerable. Other Sophos Antivirus products may also be vulnerable. Windows versions of the Sophos Antivirus product do not appear to be vulnerable. V. WORKAROUND Disabling the option to scan within archives will prevent exploitation of this vulnerability. VI. VENDOR RESPONSE Sophos has addressed this problem with new versions of their products. See http://www.sophos.com/support/knowledgebase/article/7609.html for more information. VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2006-5646 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 09/28/2006 Initial vendor notification 10/02/2006 Initial vendor response 12/08/2006 Coordinated public disclosure IX. CREDIT This vulnerability was reported to iDefense by Damian Put <pucik@overflow.pl>. Get paid for vulnerability research http://labs.idefense.com/methodology/vulnerability/vcp.php Free tools, research and upcoming events http://labs.idefense.com/ X. LEGAL NOTICES Copyright © 2006 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 e-mail 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. - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. 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Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 If you believe that your computer system has been compromised or attacked in any way, we encourage you to let us know by completing the secure National IT Incident Reporting Form at: http://www.auscert.org.au/render.html?it=3192 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQCVAwUBRXzfaih9+71yA2DNAQIixAP/X0zWkz+y8ETJ4JqnGhd1mpF6KHeLdnaJ laGaTc8XdZ1lJJCLoQGP/1aRrtKqD8T1MRRLrQPHQsG9ZNymia1yOegirfS7TJY1 L8rlwDAMaL0JJyAI3uOr9dJ9S0ofEZKvjrRof+DTPWLFSL89WB9u7rV2nppSh3Nc IUk2gZIGsKk= =fEfq -----END PGP SIGNATURE-----