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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2005.0843 -- iDEFENSE Security Advisory 10.24.05 SCO Openserver authsh 'Home' Buffer Overflow Vulnerability 25 October 2005 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: authsh Publisher: iDEFENSE Operating System: SCO OpenServer 5.0.7 and prior Impact: Root Compromise Access: Existing Account CVE Names: CVE-2005-2926 Original Bulletin: http://www.idefense.com/application/poi/display?id=327 The original advisory, published by SCO, can be found at: ftp://ftp.sco.com/pub/updates/OpenServer/SCOSA-2005.40/SCOSA-2005.40.txt - --------------------------BEGIN INCLUDED TEXT-------------------- SCO Openserver authsh 'Home' Buffer Overflow Vulnerability iDEFENSE Security Advisory 10.24.05 http://www.idefense.com/application/poi/display?type=vulnerabilities October 24, 2005 I. BACKGROUND SCO OpenServer is a UNIX-like operating system for x86 platforms. II. DESCRIPTION Local exploitation of a buffer overflow vulnerability in The SCO Group Inc.'s Openserver operating system could allow an attacker to gain root privileges. The authsh utility is a standard binary distributed with the Openserver platform. The vulnerability specifically exists because of a lack of bounds checking on the value given to the "HOME" environment variable. Local attackers can supply a specially crafted string to overflow a stack buffer and execute arbitrary code with group auth privileges. III. ANALYSIS Successful exploitation of this vulnerability will result in execution of arbitrary code with permissions of the running process. The binary is setgid auth by default and can be used by attackers with a local account to gain root privileges, as the group auth has write access to system authentication information. An attacker would only need to modify the system passwd file to grant an account they control superuser privileges. IV. DETECTION iDEFENSE has confirmed the existence of this vulnerability in SCO Openserver 5.0.7. It is suspected that earlier versions are also vulnerable. V. WORKAROUND As a workaround solution, remove the setgid bit from the authsh binary until a vendor patch can be applied. # chmod -g /opt/K/SCO/Unix/5.0.7Hw/usr/lib/sysadm/authsh VI. VENDOR RESPONSE The vendor has released the following advisory for this issue: ftp://ftp.sco.com/pub/updates/OpenServer/SCOSA-2005.40/SCOSA-2005.40.txt VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2005-2926 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 09/08/2005 Initial vendor notification 09/09/2005 Initial vendor response 10/24/2005 Public disclosure IX. CREDIT iDEFENSE Labs is credited with the discovery of this vulnerability. Get paid for vulnerability research http://www.idefense.com/poi/teams/vcp.jsp Free tools, research and upcoming events http://labs.idefense.com 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 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. 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: 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 iQCVAwUBQ114lyh9+71yA2DNAQJAuQP/fMq9ZBQV96i2CKaNUUxAUWVoGjBop2+w Cx6HcumU5A8pztpnmPEUqlhpiS69wELIJdaySos5uJaKyJ4HbX4SJlLwq7eEHyMF ia5Sznd92xomJ0IoU8xkK5FZoKSzqKKOjNAXBZ2geq1BIpfrshYG6wIW4r7adYik VOPgG1Gl3F0= =RM7T -----END PGP SIGNATURE-----