-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Solaris 2.x fdformat Buffer Overflow Vulnerability March 24, 1997 18:00 GMT Number H-44 ______________________________________________________________________________ PROBLEM: A vulnerability exists in fdformat (1). PLATFORM: All platforms running Solaris 2.4, 2.5, 2.5.1. Earlier versions may also be vulnerable. DAMAGE: This vulnerability may allow local users to gain root privileges. SOLUTION: Until patches are available, take the steps outlined in Section 3 as soon as possible. ______________________________________________________________________________ VULNERABILITY Exploit details involving this vulnerability have been made ASSESSMENT: publicly available. ______________________________________________________________________________ [ Start AUSCERT Advisory ] =========================================================================== AA-97.11 AUSCERT Advisory Solaris 2.x fdformat Buffer Overflow Vulnerability 24 March 1997 Last Revised: - ------------------------------------------------------------------------------ AUSCERT has received information that a vulnerability exists in fdformat(1), distributed under Solaris 2.4, 2.5 and 2.5.1. Earlier versions may be vulnerable. 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 fdformat(1) is a utility for formatting both diskettes and PCMCIA memory cards. Due to insufficient bounds checking on arguments which are supplied by users, it is possible to overwrite the internal stack space of the fdformat program while it is executing. By supplying a carefully designed argument to the fdformat program, intruders may be able to force fdformat to execute arbitrary commands. As fdformat is setuid root, this may allow intruders to run arbitrary commands with root privileges. Sites can determine if this program is installed by using: % ls -l /usr/bin/fdformat fdformat is installed by default in /usr/bin. 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 fdformat by immediately applying the workaround given in Section 3.1. 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 execute permissions To prevent the exploitation of the vulnerability described in this advisory, AUSCERT recommends that the setuid permissions be removed from the fdformat program immediately. # ls -l /usr/bin/fdformat -r-sr-xr-x 1 root bin 26284 Oct 25 1995 /usr/bin/fdformat # chmod 555 /usr/bin/fdformat # ls -l /usr/bin/fdformat -r-xr-xr-x 1 root bin 26284 Oct 25 1995 /usr/bin/fdformat 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 fdformat 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 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. 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, DOE contractors, and the NIH. 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, DOE contractor sites, and the NIH 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 (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. 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 OHara, 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, ESnet, and NIH 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 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. 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. LAST 10 CIAC BULLETINS ISSUED (Previous bulletins available from CIAC) H-34: Vulnerability in innd H-35: HP-UX vgdisplay command Vulnerability H-36: Solaris 2.x CDE sdtcm_convert Vulnerability H-37: Solaris 2.x passwd buffer Overrun Vulnerability H-38A: Internet Explorer 3.x Vulnerabilities H-39: SGI IRIX fsdump Vulnerability H-40: DIGITAL Security Vulnerabilities (DoP, delta-time) H-41: Solaris 2.x eject Buffer Overrun Vulnerability H-42: HP MPE/iX with ICMP Echo Request (ping) Vulnerability H-43: Update on the Vulnerability in innd -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQCVAwUBMzbOf7nzJzdsy3QZAQGbuAP/cWI0IQNicMjjodPXtF3ypgEEjwMTNO08 9GrGv4Ayrj8pkWa0hzP4zGU/5JSXiH4hUqEeNzfXUTOX7twi1SJsOdlMU1RBiTrx GmaHzK3zpe5Q/uI0poRjpcFOAKjc7lKU8vjJGNsE61Ws7rp8UAfEYzopYLOmel3I 4lLxcoGYAcg= =WXhU -----END PGP SIGNATURE-----