June 21, 2000 21:00 GMTNumber K-052
PROBLEM: The cdmount program allows regular users to mount CD-ROM filesystems. A malicious user could execute cdmount giving commands containing shell metacharacters. PLATFORM: AIX systems with the LPP UMS.objects 126.96.36.199 and below installed. DAMAGE: A malicious user can run arbitrary commands, as root, through shell metacharacter command manipulation. SOLUTION: IBM is currently working on the issue in APAR 4.3x: IY10903 (Authorized Problem Analysis Report). Apply one of the temporary fixes, as suggested by the advisory.
VULNERABILITYThe risk is MEDIUM. The capability currently exists for root ASSESSMENT: command execution.
[****** Begin ISS Advisory ******] --------------------------------------------------------------------------- -----BEGIN PGP SIGNED MESSAGE----- Internet Security Systems Security Advisory June 20, 2000 Insecure call of external program in AIX cdmount Synopsis: The AIX cdmount program allows regular users to mount CD-ROM filesystems. This program is basically a SUID to root wrapper of the mount command. Insecure handling of the arguments to cdmount may allow a local regular user to execute commands as root. Impact: Local users may gain root privileges. Affected Versions: AIX systems with the LPP UMS.objects 188.8.131.52 and below installed. Use the command 'lslpp -l UMS.objects' to verify if a vulnerable version is installed. Description: The cdmount program is part of the AIX UltiMedia Services (UMS) package. UMS provides multimedia applications to AIX workstations. The cdmount program is normally used as a helper to UMS multimedia players. It has SUID root permissions to allow regular users to mount a CD-ROM. The system()library subroutine is used within cdmount to invoke the mount program.. This subroutine spawns a shell to execute the mount command with arguments provided by the user. An attacker may execute arbitrary commands as root by calling cdmount with arguments containing shell metacharacters. Recommendations: ISS recommends removing the SUID bit from cdmount by executing the following command: # chmod 555 /usr/lpp/UMS/bin/cdmount IBM is currently working on the following APAR (Authorized Problem Analysis Report), which will be available soon: APAR 4.3.x: IY10903 Until the official fix is available, if UMS is not being used IBM recommends uninstalling UMS or removing the SUID bit from cdmount. APARs may be ordered using Electronic Fix Distribution (via FixDist) or from the IBM Support Center. For more information on FixDist, go to http://service.software.ibm.com/support/rs6000/ or send an email to firstname.lastname@example.org with a subject of "FixDist". Additional Information: The Common Vulnerabilities and Exposures (CVE) project has assigned the name CAN-2000-0466 to this issue. This is a candidate for inclusion in the CVE list http://cve.mitre.org/, which standardizes names for security problems. Credits: This vulnerability was discovered and researched by Oliver Atoa-Ortiz of the ISS X-Force. ISS would like to thank IBM for their response and handling of this vulnerability. ______ About Internet Security Systems (ISS) Internet Security Systems (ISS) is a leading global provider of security management solutions for the Internet. By providing industry-leading SAFEsuite security software, remote managed security services, and strategic consulting and education offerings, ISS is a trusted security provider to its customers, protecting digital assets and ensuring safe and uninterrupted e-business. ISS' security management solutions protect more than 5,500 customers worldwide including 21 of the 25 largest U.S. commercial banks, 10 of the largest telecommunications companies and over 35 government agencies. Founded in 1994, ISS is headquartered in Atlanta, GA, with additional offices throughout North America and international operations in Asia, Australia, Europe, Latin America and the Middle East. For more information, visit the Internet Security Systems web site at www.iss.net or call 888-901-7477. Copyright (c) 2000 Internet Security Systems, Inc. Permission is hereby granted for the redistribution of this Alert electronically. It is not to be edited in any way without express consent of the X-Force. If you wish to reprint the whole or any part of this Alert in any other medium excluding electronic medium, please email email@example.com for permission. Disclaimer The information within this paper may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties with regard to this information. In no event shall the author be liable for any damages whatsoever arising out of or in connection with the use or spread of this information. Any use of this information is at the user's own risk. X-Force PGP Key available at: http://xforce.iss.net/sensitive.php/ as well as on MIT's PGP key server and PGP.com's key server. Please send suggestions, updates, and comments to X-Force: firstname.lastname@example.org of Internet Security Systems, Inc. Revision History June 20, 2000: Initial release. -----BEGIN PGP SIGNATURE----- Version: 2.6.3a Charset: noconv iQCVAwUBOU/eBjRfJiV99eG9AQFmlQQAsLAYTP2T8uk29oSS0WlzhKYDB7W0ZBkz s8466W0VyqPz8RATUJYsISMO8RhDrM2SKaEOkGHcDReQ9yZx7lrbZCVqZu7DaunM xmYxchf3TOzmc2pFhJG5joNTI13iTEzefh+Xv+hHwiU8sL0POppUn4Hvjb3QjYNi oUg5RHGfhpk= =Qx/U -----END PGP SIGNATURE----- [****** End ISS Advisory ******]
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