-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Solaris ffbconfig Buffer Overrun Vulnerability February 13, 1997 18:00 GMT Number H-30 ______________________________________________________________________________ PROBLEM: A vulnerability exists in ffbconfig program. PLATFORM: All systems running Solaris 2.4 and 2.5.1 with the Fast Frame Buffer (FFB) Graphics Accelerator card installed. DAMAGE: This vulnerability may allow local users to gain root privileges. SOLUTION: Until patches are available it is recommended that sites apply the workaround given in Section 3. ______________________________________________________________________________ VULNERABILITY Exploit details involving this vulnerability have been made ASSESSMENT: publicly available. ______________________________________________________________________________ [ Start AUSCERT Advisory ] =========================================================================== AA-97.06 AUSCERT Advisory Solaris ffbconfig Buffer Overrun Vulnerability 13 February 1997 Last Revised: -- - ---------------------------------------------------------------------------- AUSCERT has received information that a vulnerability exists in ffbconfig(1m), distributed under Solaris 2.5 and 2.5.1. This vulnerability may allow local users to gain root privileges. Exploit information involving this vulnerability has been made publicly available. At this stage, AUSCERT is unaware of any official vendor patches. AUSCERT recommends that sites apply the workaround given in Section 3 until vendor patches are made available. This advisory will be updated as more information becomes available. - ---------------------------------------------------------------------------- 1. Description ffbconfig is a program used to configure the Fast Frame Buffer (FFB) Graphics Accelerator, and is part of the FFB Configuration Software package, SUNWffbcf. This software is only of use if the FFB Graphics accelerator card is installed. If the device /dev/fbs/ffb0 exists, it may indicate that the card is installed. Due to insufficient bounds checking on arguments which are supplied by users, it is possible to overwrite the internal stack space of the ffbconfig program while it is executing. By supplying a carefully designed argument to the ffbconfig program, intruders may be able to force ffbconfig to execute arbitrary commands. As ffbconfig is setuid root, this may allow intruders to run arbitrary commands with root privileges. ffbconfig was first released under Solaris 2.5 and 2.5.1, and this vulnerability is known to affect both these releases. Sites can determine if this package is installed by checking for the SUNWffbcf package: % /usr/bin/pkginfo -l SUNWffbcf ffbconfig is installed by default in /usr/sbin. Sites are encouraged to check for the presence of this program regardless of the version of Solaris installed. Exploit information involving this vulnerability has been made publicly available. Sun Microsystems has informed AUSCERT that they are currently working on this vulnerability. 2. Impact Local users may gain root privileges. 3. Workarounds/Solution AUSCERT recommends that sites prevent the exploitation of this vulnerability in ffbconfig by immediately applying the workaround given in Section 3.1. If the SUNWffbcf package is not required, it is recommended that sites remove it from their systems (Section 3.2). Currently there are no vendor patches available that address this vulnerability. AUSCERT recommends that official vendor patches be installed when they are made available. 3.1 Remove setuid and non-root execute permissions To prevent the exploitation of the vulnerability described in this advisory, AUSCERT recommends that the setuid permissions be removed from the ffbconfig program immediately. As ffbconfig will no longer work for non-root users, it is recommended that the execute permissions also be removed. # ls -l /usr/sbin/ffbconfig -r-sr-xr-x 1 root bin 31436 Oct 14 1995 /usr/sbin/ffbconfig # chmod 500 /usr/sbin/ffbconfig # ls -l /usr/sbin/ffbconfig -r-x------ 1 root bin 31436 Oct 14 1995 /usr/sbin/ffbconfig 3.2 Remove the SUNWffbcf package If the FFB graphics accelerator card is not installed, the SUNWffbcf package will not be required and sites are encouraged to remove it completely from their systems. This can be done by running, as root, the command: # /usr/sbin/pkgrm SUNWffbcf There are also a number of other packages which are also associated with the FFB Graphics Accelerator: SUNWffb FFB System Software (Device Driver) SUNWffbmn On-Line FFB Manual Pages SUNWffbw FFB Window System Support SUNWffbxg FFB XGL support Although there is nothing to suggest that these packages contain vulnerabilities, if you do not require their functionality, you may also wish to remove them with the /usr/sbin/pkgrm command. 4. Additional measures Most Unix systems ship with numerous programs which have setuid or setgid privileges. Often the functionality supplied by these privileged programs is not required by many sites. The large number of privileged programs that are shipped by default are to cater for all possible uses of the system. AUSCERT encourages sites to examine all the setuid/setgid programs and determine the necessity of each program. If a program does not absolutely require the setuid/setgid privileges to operate (for example, it is only run by the root user), the setuid/setgid privileges should be removed. Furthermore, if a program is not required at your site, then all execute permissions should be removed. A sample command to find all setuid/setgid programs is (run as root): # find / \( -perm -4000 -o -perm -2000 \) -type f -exec ls -l {} \; It is AUSCERT's experience that many vulnerability are being discovered in setuid/setgid programs which are not necessary for the correct operation of most systems. Sites can increase their security by removing unnecessary setuid/setgid programs. For example, the functionality provided by the ffbconfig program is not needed by many sites. If sites had previously disabled this program, they would not have been susceptible to this latest vulnerability. - ---------------------------------------------------------------------------- [ End AUSCERT Advisory ] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of AUSCERT, Sun Microsystems & DFN-CERT for the 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 (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. 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World Wide Web: http://ciac.llnl.gov/ Anonymous FTP: ciac.llnl.gov (128.115.19.53) Modem access: +1 (510) 423-4753 (28.8K baud) +1 (510) 423-3331 (28.8K 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. 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A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. 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) H-20: Vulnerability in IRIX csetup H-21: HP Security Vulnerabilities (newgrp, authentication, passwor H-22: talkd Buffer Overrun Vulnerability H-23: Sendmail MIME Conversion Buffer Overrun Vulnerability H-24: IBM AIX(r) "gethostbyname()" Buffer Overrun Vulnerability H-25: Vulnerability in rlogin/term H-26: FreeBSD setlocale() Vulnerability H-27: HP-UX vgdisplay Buffer Overrun Vulnerability H-28: SGI IRIX startmidi/stopmidi Vulnerability H-29: HP-UX sendmail Patches Vulnerability RECENT CIAC NOTES ISSUED (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 PKZ300B Trojan, Logdaemon/FreeBSD, vulnerability in S/Key, EBOLA Virus Hoax, and Caibua Virus Notes 11 - 7/31/95 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 Securely configuring Public Telnet Services, X Windows, beta release of Merlin, Microsoft Word Macro Viruses, Allegations of Inappropriate Data Collection in Win95 Notes 96-01 - 3/18/96 Java and JavaScript Vulnerabilities, FIRST Conference Announcement, Security and Web Search Engines, Microsoft Word Macro Virus Update -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQCVAwUBMwTwkbnzJzdsy3QZAQFppQQA5ahsUROsyxkVHttUT7R48md/ZmuXZZ6s BbTUYgAOsaTc2lLT9Ywch0vYxco8lB6scEwaQRk4DWWYLUz4iSAmlwlHahrg7FjJ d3aBR0ICNDc3qtx/e3ajV/ef5VfiSG34EZDr23bTgS3dHzBP+9gJfPVoC/y0JNS7 KKvAWPQgTbo= =yTj7 -----END PGP SIGNATURE-----