-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN SunOS 4.1.X Loadmodule Vulnerability November 3, 1995 01:00 GMT Number G-02 _______________________________________________________________________________ PROBLEM: A bug exists in the loadmodule(8) program which, when exploited, can allow a user to gain root access. PLATFORM: SunOS 4.1.x DAMAGE: This problem makes it possible for a local user to obtain root access. SOLUTION: Apply either the fix or the patch described below. - ------------------------------------------------------------------------------- VULNERABILITY An exploitation script has been found to be publicly available. ASSESSMENT: - ------------------------------------------------------------------------------- Introduction The loadmodule(8) program is used by the xnews(1) window system to dynamically load kernel driver modules. Two of these module provide a SunView binary compatibility mode. However, these modules introduce a vulnerability which makes it possible for a normal user to gain unauthorized access. Solutions A. Obtain and install the appropriate patches according to the instructions included with the patches. Patches are available through your local Sun Answer Center and by FTP from ftp://sunsolve1.sun.com/pub/patches/100448-03.tar.Z Module Patch ID Filename ---------- --------- --------------- loadmodule 100448-03 100448-03.tar.Z Checksum: MD5 (100448-03.tar.Z) = 183a22f0a2f6020f1389b6aeea5ca6c6 B. Because, in general, a set-user-id program can lead to security exposures, you should also do at least step 1 below. We recommend doing steps 2 and 3 as well. The intent of these directions is make the loadmodule(8) program work only for the super-user (currently it works for all users because it is set-user-id) and to execute it each time the system boots. By following these directions, users who require SunView binary compatibility will have it available to them. 1. If you do not need SunView binary compatibility, then as root, turn off setuid root on the loadmodule(8) program with # /bin/chmod u-s /usr/openwin/bin/loadmodule 2. If your users need SunView binary compatibility, you can enable it immediately--that is without having to reboot your system--with the following script. ------------------------cut here--8<------------------------ ARCH=`/bin/arch -k` OBJ=/sys/${ARCH}/OBJ LM=/usr/openwin/bin/loadmodule /bin/chmod u-s $LM if [ -f $OBJ/evqmod-${ARCH}.o ]; then if /usr/etc/modstat | /bin/egrep -s evqmod ; then echo evq: already loaded elif $LM evqmod-${ARCH}.o evqload; then echo evq: loaded else echo evq: unable to load module fi fi if [ -f $OBJ/winlock-${ARCH}.o ]; then if /usr/etc/modstat | /bin/egrep -s winlock ; then echo winlock: already loaded elif $LM winlock-${ARCH}.o winlockload; then echo winlock: loaded else echo winlock: unable to load module fi fi ------------------------cut here--8<------------------------ As a suggestion, store this script in /tmp/esbc and then execute it as root with: # sh /tmp/esbc 3. If you've done step 2 above, the module loadings will disappear the next time you reboot your system. To make them permanent-- that is to make these module loadings occur each time your system is rebooted--add the script to the end of your /etc/rc.local file. _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of the CERT Coordination Center for information contained in 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: +1 510-422-8193 FAX: +1 510-423-8002 STU-III: +1 510-423-2604 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: +1 (510) 423-4753 (14.4K baud) +1 (510) 423-3331 (9600 baud) CIAC has several self-subscribing mailing lists for electronic publications: 1. 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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. 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LAST 10 CIAC BULLETINS ISSUED (Previous bulletins available from CIAC) (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 (F-28) Vulnerability in SunOS 4.1.* Sendmail (-oR option) (F-28) Vulnerability in SunOS 4.1.* Sendmail (-oR option) (G-1) Telnetd Vulnerability RECENT CIAC NOTES ISSUED IN FY1995 (Previous Notes available from CIAC) Notes 07 - 3/29/95 A comprehensive review of SATAN Notes 08 - 4/4/95 A Courtney update Notes 09 - 4/24/95 More on the "Good Times" virus urban legend Notes 10 - 6/16/95 Discusses the PKZ300B Trojan, Logdaemon/FreeBSD vulnerability in S/Key, EBOLA Virus Hoax, and Caibua Virus Notes 11 - 7/31/95 Features include a Virus Update, Hats Off to Administrators, America On-Line Virus Scare, SPI 3.2.2 Released, The Die_Hard Virus Notes 12 - 9/12/95 Features include discussions on securely configuring Public Telnet Services, X Windows and announces the beta release of Merlin, describes the Microsoft Word Macro Viruses, and examines allegations of Inappropriate Data Collection in Win95 -----BEGIN PGP SIGNATURE----- Version: 2.6.2 Comment: Processed by Mailcrypt 3.3, an Emacs/PGP interface iQCVAwUBMJmAtrnzJzdsy3QZAQEFFgP/VdkJBIzW1kiHdQDaO+mLYuFQ275M+eWM FVn3rC+xPYvB79+P6CTmGIzq/h4MuREWK3UztyvcfvdMYfjZEL8bHqAvFeVl7qPK cqOercQ7PWpplTqdjUiC9jhM5+sETq6KqLP0/GnXCAxupAv5/NewF/njssreq4yJ zIGWbJIDQ6M= =xRwS -----END PGP SIGNATURE-----