-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =============================================================================== >> CERT-NL, 01-Mar-2000 << >> All CERT-NL information has been moved to http://cert.surfnet.nl. Links << >> to CERT-NL information contained in this advisory are therefore outdated. << >> << >> CERT-NL also has stopped the CERT-CC-Mirror service. Due to this the << >> links to the CERT-CC mirror are obsolete. Visit the CERT-CC site for the << >> complete CERT-CC advisory texts: http://www.cert.org << =============================================================================== =============================================================================== Security Advisory CERT-NL =============================================================================== Author/Source : Olav ten Bosch Index : S-97-11 Distribution : World Page : 1 Classification: External Version: 1 Subject : Solaris ffbconfig vulnerability Date : 14-Feb-97 =============================================================================== By courtesy of AUSCERT we received the following information: 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. - - --------------------------------------------------------------------------- AUSCERT thanks Sun Microsystems and DFN-CERT for their assistance in this matter. - - --------------------------------------------------------------------------- ============================================================================== CERT-NL is the Computer Emergency Response Team for SURFnet customers. SURFnet is the Dutch network for educational, research and related institutes. CERT-NL is a member of the Forum of Incident Response and Security Teams (FIRST). All CERT-NL material is available under: http://cert.surfnet.nl/ In case of computer or network security problems please contact your local CERT/security-team or CERT-NL (if your institute is NOT a SURFnet customer please address the appropriate (local) CERT/security-team). 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