-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Vulnerability in SunOS 4.1.* Sendmail (-oR option) September 8, 1995 1200 PDT Number F-28 _______________________________________________________________________________ PROBLEM: A vulnerability exists in SunOS 4.1.* systems that could allow an intruder to exploit a vulnerability in the way sendmail(8) uses the -oR option PLATFORM: SunOS 4.1.* based systems DAMAGE: Users logged into a system may gain unauthorized root privileges. SOLUTION: See the notes below AVAILABILITY: See the notes below _______________________________________________________________________________ VULNERABILITY Unprivileged users who are logged on to a system can use this ASSESSMENT: vulnerability to gain unauthorized root privileges. An exploit program for this vulnerability has been published by 8lgm. CIAC advises that one of the workarounds described below be performed immediately. _______________________________________________________________________________ CRITICAL Information on the sendmail -oR vulnerability in SunOS CIAC has received information that a vulnerability has been identified in the sendmail(8) program on SunOS 4.1.X systems that can be exploited to gain root access. The basic problem involves misusing the -oR option in sendmail which uses popen(). Detailed Description ____________________ sendmail(8) on SunOS 4.1.X systems when using the -oR option, uses popen() to return undeliverable mail. Local unprivileged users can use this to obtain root access. This vulnerability has been verified as being present in Sun sendmail including the current patches (currently at 100377-19 (4.1.3), 101665-04 (4.1.3_U1), 102423-01 (4.1.4)) as of the time of this printing. A vulnerability script to exploit this bug has been released to the public. WORKAROUNDS ___________ CIAC recommends that you apply patches for this vulnerability when they become available from Sun Microsystems. At the time of this printing, patches were not available, but in final testing. One workaround is to install Eric Allman's sendmail (current version as of printing is 8.6.12). This version of sendmail has had many bugs fixed, but could require significant effort to install and may require rewriting of sendmail.cf files. The software and documentation is available from: ftp://ftp.cs.berkeley.edu/ucb/sendmail A second workaround is in the form of a sendmail "wrapper" program. The program was written by members of the AUSCERT team, and is also available from: ftp://ftp.cs.berkeley.edu/ucb/sendmail/sendmail_wrapper.c This program provides workarounds for this bug as well as several others. This should be considered a temporary fix however, and you should install the Sun patches as soon as they become available. Documentation on installation of this wrapper is provided in the file (sendmail_wrapper.c). _______________________________________________________________________________ CIAC wishes to thank the AUSCERT team and 8lgm for providing information for this bulletin. _______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy. CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE and DOE contractors, and CIAC can be contacted at: Voice: 510-422-8193 FAX: 510-423-8002 STU-III: 510-423-2604 E-mail: ciac@llnl.gov For emergencies and off-hour assistance, DOE and DOE contractor sites may contact CIAC 24-hours a day. During off hours (5PM - 8AM PST), call the CIAC voice number 510-422-8193 and leave a message, or call 800-759-7243 (800-SKY-PAGE) to send a Sky Page. CIAC has two Sky Page PIN numbers, the primary PIN number, 8550070, is for the CIAC duty person, and the secondary PIN number, 8550074 is for the CIAC Project Leader. Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://ciac.llnl.gov/ Anonymous FTP: ciac.llnl.gov (128.115.19.53) Modem access: (510) 423-4753 (14.4K baud) (510) 423-3331 (9600 baud) CIAC has several self-subscribing mailing lists for electronic publications: 1. CIAC-BULLETIN for Advisories, highest priority - time critical information and Bulletins, important computer security information; 2. CIAC-NOTES for Notes, a collection of computer security articles; 3. SPI-ANNOUNCE for official news about Security Profile Inspector (SPI) software updates, new features, distribution and availability; 4. SPI-NOTES, for discussion of problems and solutions regarding the use of SPI products. Our mailing lists are managed by a public domain software package called ListProcessor, which ignores E-mail header subject lines. To subscribe (add yourself) to one of our mailing lists, send the following request as the E-mail message body, substituting CIAC-BULLETIN, CIAC-NOTES, SPI-ANNOUNCE or SPI-NOTES for list-name and valid information for LastName FirstName and PhoneNumber when sending E-mail to ciac-listproc@llnl.gov: subscribe list-name LastName, FirstName PhoneNumber e.g., subscribe ciac-notes OUHara, Scarlett W. 404-555-1212 x36 You will receive an acknowledgment containing address, initial PIN, and information on how to change either of them, cancel your subscription, or get help. PLEASE NOTE: Many users outside of the DOE and ESnet computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained by sending email to docserver@first.org with an empty subject line and a message body containing the line: send first-contacts. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. CIAC BULLETINS ISSUED IN FY95 (Previous bulletins available from CIAC) (F-01) SGI IRIX serial_ports Vulnerability (F-02) Summary of HP Security Bulletins (F-03) Restricted Distribution (F-04) Security Vulnerabilities in DECnet/OSI for OpenVMS (F-05) SCO Unix at, login, prwarn, sadc, and pt_chmod Patches Available (F-06) Novell UnixWare sadc, urestore, and suid_exec Vulnerabilities (F-07) New and Revised HP Bulletins (F-08) Internet Address Spoofing and Hijacked Session Attacks (F-09) Unix /bin/mail Vulnerabilities (F-10) HP-UX Remote Watch (F-11) Unix NCSA httpd Vulnerability (F-12) Kerberos Telnet Encryption Vulnerability (F-13) Unix sendmail vulnerabilities (F-14) HP-UX Malicious Code Sequences (F-15) HP-UX "at" and "cron" vulnerabilities (F-16) SGI IRIX Desktop Permissions Tool Vulnerability (F-17) Limited Distribution (F-18) MPE/iX Vulnerabilities (F-19) Protecting HP-UX Systems Against SATAN (F-20) Security Administrator Tool for Analyzing Networks (SATAN) (F-21) Protecting SUN OS Systems Against SATAN (F-22) SATAN Password Disclosure (F-23) Protecting IBM AIX Systems Against SATAN (F-24) Protecting SGI IRIX Systems Against SATAN (F-25) Cisco IOS Router Software Vulnerability (F-26) OSF/DCE Security Hole (F-27) Incorrect Permissions on /tmp CIAC NOTES ISSUED IN FY1995 (Previous Notes available from CIAC) 04c December 8, 1994 05d January 11, 1995 06 March 22, 1995 07 March 29, 1995 08 April 4, 1995 09 April 24, 1995 10a June 16, 1995 11 July, 31, 1995 -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQCVAwUBMFCPpbnzJzdsy3QZAQGg9QP/QlLIroWTs6QZ4Nb9q6PJMvQNeahPlHvJ PNXUN/50ExkUKrqSnqB/JLW5Vnnqzj5U7x3vWHelTRpKm6M4tDIfRGHefuBX1/d3 aBQaStTG1Fsiwvv/SOMu6FZW3uKEfEEkEmYnb05zYw58O9/q4CF8ML9n3pcmDAZM of3U9jREmdY= =OUd+ -----END PGP SIGNATURE-----