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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2005.0111 -- iDEFENSE Security Advisory 02.07.05 IBM AIX chdev Local Format String Vulnerability 8 February 2005 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: chdev Publisher: iDEFENSE Operating System: AIX Impact: Root Compromise Execute Arbitrary Code/Commands Access: Existing Account Original Bulletin: http://www.idefense.com/application/poi/display?id=192&type=vulnerabilities - --------------------------BEGIN INCLUDED TEXT-------------------- IBM AIX chdev Local Format String Vulnerability iDEFENSE Security Advisory 02.07.05 http://www.idefense.com/application/poi/display?type=vulnerabilities February 07, 2005 I. BACKGROUND The chdev program is a setuid root application, installed by default under multiple versions of IBM AIX, that facilitates the changing of device characteristics. II. DESCRIPTION Local exploitation of a format string vulnerability in the chdev command included by default in multiple versions of IBM Corp.'s AIX operating system could allow for arbitrary code execution as the root user. The vulnerability specifically exists due to an improperly used formatted printing function. When provided with an incorrect argument (argv) that contains a format string, the format string will be fed into a formatted printing function, and the user supplied format string will be evaluated, allowing for a malicious user to examine stack memory and write to arbitrary memory locations. With a properly crafted string, this can lead to the execution of arbitrary code. III. ANALYSIS This vulnerability can only be exploited by a local user who has been granted access to the "system" group. Successful exploitation leads to root-level access. Due to the nature of the vulnerability, information leakage is trivial and aids the attacker in exploitation. IV. DETECTION iDEFENSE has confirmed the existence of this vulnerability in IBM AIX version 5.2. It is suspected that previous versions are also vulnerable. V. WORKAROUND Only allow trusted users local access to security critical systems. Only allow trusted system administrators access to the "system" group. Alternately, remove the setuid bit from chdev using chmod u-s /usr/sbin/chdev. VI. VENDOR RESPONSE The vendor has not released a patch for this issue, however, the following details have been published: http://www-1.ibm.com/support/docview.wss?uid=isg1IY67455 In addition, a security advisory will be posted at the following site: https://techsupport.services.ibm.com/server/pseries.subscriptionSvcs?mode=1 Please note that a free signup is required to access the security advisory. VII. CVE INFORMATION A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not been assigned yet. VIII. DISCLOSURE TIMELINE 12/21/2004 Initial vendor notification 01/07/2005 Initial vendor response 02/07/2005 Coordinated public disclosure IX. CREDIT iDEFENSE Labs is credited with this discovery. Get paid for vulnerability research http://www.idefense.com/poi/teams/vcp.jsp X. LEGAL NOTICES Copyright (c) 2005 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 firstname.lastname@example.org 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 email@example.com 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. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. 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: firstname.lastname@example.org 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 iQCVAwUBQggFOih9+71yA2DNAQIQqQP9EKT/jdKyVQMQlgMROkaiqxi+amjhJyg0 boLECe24Yd7xXaHd/0Zqm9HA/g4+xU1gu59Ty9iaMLHhrv4PU7PLGPnzq5St6dEg pY4pzD+jbHsybIwz4+H8e0M/6SaI1LBMijJQSusf6z8NsTATx8XdEly3b6RIZ2X3 fU+c3VnadfI= =9Ikx -----END PGP SIGNATURE-----