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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2007.0083 -- [Win][Linux] RARLabs Unrar Password Prompt Buffer Overflow Vulnerability 8 February 2007 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Unrar Command Line Utility for Windows 3.61 Unrar Command Line Utility for Linux 3.60 Publisher: iDefense Operating System: Windows Linux variants Impact: Execute Arbitrary Code/Commands Access: Remote/Unauthenticated Original Bulletin: http://www.idefense.com/intelligence/vulnerabilities/display.php?id=472 - --------------------------BEGIN INCLUDED TEXT-------------------- RARLabs Unrar Password Prompt Buffer Overflow Vulnerability iDefense Security Advisory 02.07.07 http://labs.idefense.com/intelligence/vulnerabilities/ Feb 07, 2007 I. BACKGROUND Unrar is a command line archive extractor for Windows and Linux. For more information visit the vendor's site at the URL shown below. http://www.rarlabs.com/ II. DESCRIPTION Remote exploitation of a stack based buffer overflow vulnerability in RARLabs Unrar may allow an attacker to execute arbitrary code with the privileges of the user opening the archive. Unrar is prone to a stack based buffer overflow when processing specially crafted password protected archives. III. ANALYSIS Exploitation of the vulnerability could allow an attacker to execute arbitrary code with the privileges of the user opening the file. Exploitation would require that an attacker hosts a maliciously crafted document on a website and entice users to visit the site. An attacker could also e-mail the malicious document and use social engineering techniques to trick the e-mail recipient into opening the document. There are several mitigating factors for this vulnerability. Nearly all Windows users will use the GUI based WinRAR to open archives, and it is not vulnerable. If users are using the vulnerable command line based unrar, they still need to interact with the program in order to trigger the vulnerability. They must respond to the prompt asking for the password, after which the vulnerability will be triggered. They do not need to enter a correct password, but they must at least push the enter key. IV. DETECTION iDefense has confirmed the existence of this vulnerability in version 3.60 for Linux and 3.61 for Windows. Previous versions may also be affected. V. WORKAROUND iDefense is currently unaware of any workarounds for this issue. VI. VENDOR RESPONSE RARLabs has addressed this vulnerability with the version 3.70 beta release of WinRAR. VII. CVE INFORMATION A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not been assigned yet. VIII. DISCLOSURE TIMELINE 12/12/2006 Initial vendor notification 01/09/2007 Initial vendor response 02/07/2007 Coordinated public disclosure IX. CREDIT The discoverer of this vulnerability wishes to remain anonymous. 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. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. 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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 iQCVAwUBRcp4aCh9+71yA2DNAQKeqAP/fH5xRwqGf/ri1qBeT6stjEl+HG4hTRC0 0gHwLN2yklwXkW24hZZg+jFrbjWsNec+lL+4bynbsO9XCXNivRG9gdZVrdFjtSMx /HvFUWeizIlGDyQWZ8VcVnNd9BhZA1HnvYA+JyT5flAKg7eVt7fLu/FCUjhPHAta cUnfTC5SxzQ= =sU5a -----END PGP SIGNATURE-----