SCO Unixware Setuid ppp prompt Buffer Overflow Vulnerability iDEFENSE Security Advisory 10.24.05 http://www.idefense.com/application/poi/display?type=vulnerabilities October 24, 2005 I. BACKGROUND SCO UnixWare is a UNIX operating system. More information is available at: http://www.sco.com/products/unixware714/ II. DESCRIPTION Local exploitation of a buffer overflow vulnerability in the ppp binary, as included in multiple versions of The SCO Group Inc.'s Unixware, allows attackers to gain root privileges. The vulnerability specifically exists because of a failure to check the length of user input. If the user running the ppp program enters an argument to the "prompt" or "defprompt" command that exceeds 256 bytes in length, a stack based overflow occurs. This leads to the execution of arbitrary code with root privileges, as ppp is setuid root by default. III. ANALYSIS Successful exploitation of this vulnerability requires that user have local access to the system; it would allow the user to gain superuser privileges. IV. DETECTION iDEFENSE has confirmed the existence of this vulnerability in SCO Unixware versions 7.1.3 and 7.1.4. All versions of SCO Unixware are suspected to be vulnerable. V. WORKAROUND As a workaround solution, remove the setuid bit from the backupsh binary until a vendor patch can be applied. # chmod u-s /usr/bin/ppp VI. VENDOR RESPONSE The vendor has released the following advisory for this issue: ftp://ftp.sco.com/pub/updates/UnixWare/SCOSA-2005.41/SCOSA-2005.41.txt VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2005-2927 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@private 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.
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