-----BEGIN PGP SIGNED MESSAGE----- ****************************************************************************** ------ ----- ----- --- ----- | ----- ---- | | | | | |--- | | | | | | | | | |-- | | | | |-- | | | | | | | | \ | | ----- ---- ----- ----- | \ ----- A D V I S O R Y 97.14 ****************************************************************************** Topic: SGI IRIX df, pset, and eject Buffer Overrun Vulnerabilities Source: CIAC Creation Date: May 27, 1997 17:00 GMT Last Updated: May 27, 1997 17:00 GMT To aid in the wide distribution of essential security information, FedCIRC is forwarding the following information from CIAC bulletin H-61. FedCIRC urges you to act on this information as soon as possible. If you have any questions, please contact FedCIRC: Telephone: +1 888 282 0870 Email: fedcirc@fedcirc.gov =======================FORWARDED TEXT STARTS HERE============================ __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN SGI IRIX df, pset, and eject Buffer Overrun Vulnerabilities May 27, 1997 17:00 GMT Number H-61 ______________________________________________________________________________ PROBLEM: Three vulnerabilities have been identified on the SGI IRIX operating system: (1) df program, (2) pset program, and (3) eject program. PLATFORM: All SGI systems running the following corresponding versions of IRIX: (1) IRIX 5.3, 6.2, and 6.3; (2) IRIX 5.3 and 6.2; and (3) Irix 6.2. Other versions may be vulnerable. DAMAGE: All three vulnerabilities may allow local users to gain root privileges. SOLUTION: Apply the suggested workarounds listed below. ______________________________________________________________________________ VULNERABILITY Exploit information involving these vulnerabilities have been ASSESSMENT: made publicly available. ______________________________________________________________________________ [ Start AUSCERT Advisories ] 1. df Buffer Overrun Vulnerability =========================================================================== AA-97.19 AUSCERT Advisory SGI IRIX df Buffer Overrun Vulnerability 26 May 1997 Last Revised: -- - - - ---------------------------------------------------------------------------- AUSCERT has received information that a vulnerability exists in df(1), distributed under IRIX 5.3, 6.2 and 6.3. Other versions may also 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 df(1) is a program used to display statistics about the amount of used and free disc space on file systems. Due to insufficient bounds checking on arguments which are supplied by users, it is possible to overwrite the internal stack space of the df program while it is executing. By supplying a carefully designed argument to the df program, intruders may be able to force df to execute arbitrary commands. As df 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 /sbin/df df is installed by default in /sbin. Sites are encouraged to check for the presence of this program regardless of the version of IRIX installed. Exploit information involving this vulnerability has been made publicly available. 2. Impact Local users may gain root privileges. 3. Workarounds/Solution AUSCERT recommends that sites prevent the exploitation of this vulnerability in df by immediately applying the workaround given in Section 3.1. If the df functionality is required by non-root users, AUSCERT recommends applying the workaround given in 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 df program immediately. As df will no longer work for non-root users, it is recommended that the execute permissions for them also be removed. # ls -l /sbin/df -r-sr-xr-x 1 root sys 23136 Nov 22 1994 /sbin/df # chmod 500 /sbin/df # ls -l /sbin/df -r-x------ 1 root sys 23136 Nov 22 1994 /sbin/df 3.2 Install df wrapper AUSCERT has developed a wrapper to help prevent programs from being exploited using the vulnerability described in this advisory. Sites which have a C compiler can obtain the source, compile and install the wrapper as described in Section 3.2.1. For sites without a C compiler, AUSCERT has made pre-compiled binaries available (Section 3.1.2). 3.2.1 Installing the wrapper from source The source for the wrapper, including installation instructions, can be found at: ftp://ftp.auscert.org.au/pub/auscert/tools/overflow_wrapper/ overflow_wrapper.c This wrapper replaces the df program and checks the length of the command line arguments which are passed to it. If an argument exceeds a certain predefined value (MAXARGLEN), the wrapper exits without executing the df command. The wrapper program can also be configured to syslog any failed attempts to execute df with arguments exceeding MAXARGLEN. For further instructions on using this wrapper, please read the comments at the top of overflow_wrapper.c. When compiling overflow_wrapper.c for use with df, AUSCERT recommends defining MAXARGLEN to be 32. The MD5 checksum for the current version of overflow_wrapper.c can be retrieved from: ftp://ftp.auscert.org.au/pub/auscert/tools/overflow_wrapper/CHECKSUM The CHECKSUM file has been digitally signed using the AUSCERT PGP key. 3.2.2 Installing the wrapper binaries Pre-compiled wrapper binary is provided for sites that wish to install the wrapper but do not have a C compiler available. AUSCERT has compiled the wrapper on IRIX 5.3, however later versions of IRIX should be able to use the wrapper binary without recompilation. The following compile time options have been used to create the binaries: REAL_PROG='"/sbin/df.real"' MAXARGLEN=32 SYSLOG More information on these options can be found in Section 3.1.1 and in the overflow_wrapper.c source code. The pre-compiled binaries for the wrapper program can be retrieved from: ftp://ftp.auscert.org.au/pub/auscert/tools/AA-97.19-df_wrapper.tar.Z The MD5 checksum for AA-97.19-df_wrapper.tar.Z is: MD5 (AA-97.19-df_wrapper.tar.Z) = 9d21e6358129cccbe3768757a5361f56 AA-97.19-df_wrapper.tar.Z contains a README file with installation instructions, as well as a pre-compiled binary. Sites are encouraged to carefully read the installation notes in the README file before installation. - - - ---------------------------------------------------------------------------- 2. pset Buffer Overrun Vulnerability =========================================================================== AA-97.20 AUSCERT Advisory SGI IRIX pset Buffer Overrun Vulnerability 27 May 1997 Last Revised: -- - - - ------------------------------------------------------------------------------ AUSCERT has received information that a vulnerability exists in pset(1M), distributed under IRIX 5.3 and 6.2. Other versions may also be vulnerable. This vulnerability may allow local users to gain the privileges of group sys. These privileges may then be leveraged 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 pset(1M) is a program used to display and modify information concerning the use of processor sets in the current system. The pset command is used on multi-processor systems to restrict the execution of different classes of jobs. Due to insufficient bounds checking on arguments which are supplied by users, it is possible to overwrite the internal stack space of the pset program while it is executing. By supplying a carefully designed argument to the pset program, intruders may be able to force pset to execute arbitrary commands. As pset is setgid sys, this may allow intruders to run arbitrary commands with the privileges of group sys. This may then be leveraged to gain root privileges. Sites can determine if this program is installed by using: % ls -l /sbin/pset pset is installed by default in /sbin. Sites are encouraged to check for the presence of this program regardless of the version of IRIX installed. Exploit information involving this vulnerability has been made publicly available. 2. Impact This vulnerability may allow local users to gain the privileges of group sys. These privileges may then be leveraged to gain root privileges. 3. Workarounds/Solution AUSCERT recommends that sites prevent the exploitation of this vulnerability in pset by immediately applying the workaround given in Section 3.1. If the pset functionality is required by non-root users, AUSCERT recommends applying the workaround given in 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 setgid and non-root execute permissions To prevent the exploitation of the vulnerability described in this advisory, AUSCERT recommends that the setgid permissions be removed from the pset program immediately. As pset will no longer work for non-root users, it is recommended that the execute permissions for them also be removed. # ls -l /sbin/pset -rwsr-sr-x 1 root sys 31704 Nov 22 1994 /sbin/pset # chmod 500 /sbin/pset # ls -l /sbin/pset -r-x------ 1 root sys 31704 Nov 22 1994 /sbin/pset 3.2 Install pset wrapper AUSCERT has developed a wrapper to help prevent programs from being exploited using the vulnerability described in this advisory. Sites which have a C compiler can obtain the source, compile and install the wrapper as described in Section 3.2.1. For sites without a C compiler, AUSCERT has made pre-compiled binaries available (Section 3.2.2). 3.2.1 Installing the wrapper from source The source for the wrapper, including installation instructions, can be found at: ftp://ftp.auscert.org.au/pub/auscert/tools/overflow_wrapper/ overflow_wrapper.c This wrapper replaces the pset program and checks the length of the command line arguments which are passed to it. If an argument exceeds a certain predefined value (MAXARGLEN), the wrapper exits without executing the pset command. The wrapper program can also be configured to syslog any failed attempts to execute pset with arguments exceeding MAXARGLEN. For further instructions on using this wrapper, please read the comments at the top of overflow_wrapper.c. When compiling overflow_wrapper.c for use with pset, AUSCERT recommends defining MAXARGLEN to be 32. The MD5 checksum for the current version of overflow_wrapper.c can be retrieved from: ftp://ftp.auscert.org.au/pub/auscert/tools/overflow_wrapper/CHECKSUM The CHECKSUM file has been digitally signed using the AUSCERT PGP key. 3.2.2 Installing the wrapper binaries Pre-compiled wrapper binary is provided for sites that wish to install the wrapper but do not have a C compiler available. AUSCERT has compiled the wrapper on IRIX 5.3, however later versions of IRIX should be able to use the wrapper binary without recompilation. The following compile time options have been used to create the binaries: REAL_PROG='"/sbin/pset.real"' MAXARGLEN=32 SYSLOG More information on these options can be found in Section 3.2.1 and in the overflow_wrapper.c source code. The pre-compiled binaries for the wrapper program can be retrieved from: ftp://ftp.auscert.org.au/pub/auscert/tools/AA-97.20-pset_wrapper.tar.Z The MD5 checksum for AA-97.20-pset_wrapper.tar.Z is: MD5 (AA-97.20-pset_wrapper.tar.Z) = 875367aec70936fc5f4531b0ba8ebc03 AA-97.20-pset_wrapper.tar.Z contains a README file with installation instructions, as well as a pre-compiled binary. Sites are encouraged to carefully read the installation notes in the README file before installation. 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 vulnerabilities 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 pset program is not needed by many sites. If sites had previously disabled this program, they would not have been susceptible to this latest vulnerability. - - - ------------------------------------------------------------------------------ 3. eject Buffer Overrun Vulnerability =========================================================================== AA-97.21 AUSCERT Advisory SGI IRIX eject Buffer Overrun Vulnerability 27 May 1997 Last Revised: -- - - - ---------------------------------------------------------------------------- AUSCERT has received information that a vulnerability exists in eject(1), distributed under IRIX 6.2. Other versions may also 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 eject(1) is a program used to eject a removable media device, such as floppy, CDROM, or tape. If the floppy or CDROM is mounted, eject will first try to unmount it. Due to insufficient bounds checking on arguments which are supplied by users, it is possible to overwrite the internal stack space of the eject program while it is executing. By supplying a carefully designed argument to the eject program, intruders may be able to force eject to execute arbitrary commands. As eject 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/sbin/eject eject is installed by default in /usr/sbin. Sites are encouraged to check for the presence of this program regardless of the version of IRIX installed. Exploit information involving this vulnerability has been made publicly available. 2. Impact Local users may gain root privileges. 3. Workarounds/Solution AUSCERT recommends that sites prevent the exploitation of this vulnerability in eject by immediately applying the workaround given in Section 3.1. If the eject functionality is required by non-root users, AUSCERT recommends applying the workaround given in 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 eject program immediately. As eject will no longer have its full functionality for non-root users, it is recommended that the execute permissions be also removed for these users. # ls -l /usr/sbin/eject -rwsr-xr-x 1 root sys 45892 Nov 28 15:09 /usr/sbin/eject # chmod 500 /usr/sbin/eject # ls -l /usr/sbin/eject -r-x------ 1 root sys 45892 Nov 28 15:09 /usr/sbin/eject 3.2 Install wrapper AUSCERT has developed a wrapper to help prevent programs from being exploited using the vulnerability described in this advisory. Sites which have a C compiler can obtain the source, compile and install the wrapper as described in Section 3.2.1. For sites without a C compiler, AUSCERT has made pre-compiled binaries available (Section 3.2.2). 3.2.1 Installing the wrapper from source The source for the wrapper, including installation instructions, can be found at: ftp://ftp.auscert.org.au/pub/auscert/tools/overflow_wrapper/ overflow_wrapper.c This wrapper replaces the eject program and checks the length of the command line arguments which are passed to it. If an argument exceeds a certain predefined value (MAXARGLEN), the wrapper exits without executing the eject command. The wrapper program can also be configured to syslog any failed attempts to execute eject with arguments exceeding MAXARGLEN. For further instructions on using this wrapper, please read the comments at the top of overflow_wrapper.c. When compiling overflow_wrapper.c for use with eject, AUSCERT recommends defining MAXARGLEN to be 32. The MD5 checksum for the current version of overflow_wrapper.c can be retrieved from: ftp://ftp.auscert.org.au/pub/auscert/tools/overflow_wrapper/CHECKSUM The CHECKSUM file has been digitally signed using the AUSCERT PGP key. 3.2.2 Installing the wrapper binaries Pre-compiled wrapper binary is provided for sites that wish to install the wrapper but do not have a C compiler available. AUSCERT has compiled the wrapper on IRIX 5.3, however later versions of IRIX should be able to use the wrapper binary without recompilation. The following compile time options have been used to create the binaries: REAL_PROG='"/usr/sbin/eject.real"' MAXARGLEN=32 SYSLOG More information on these options can be found in Section 3.2.1 and in the overflow_wrapper.c source code. The pre-compiled binaries for the wrapper program can be retrieved from: ftp://ftp.auscert.org.au/pub/auscert/tools/AA-97.21-eject_wrapper.tar.Z The MD5 checksum for AA-97.21-eject_wrapper.tar.Z is: MD5 (AA-97.21-eject_wrapper.tar.Z) = 276bf0f51c89e54d4c584a9e8dd9265d AA-97.21-eject_wrapper.tar.Z contains a README file with installation instructions, as well as a pre-compiled binary. Sites are encouraged to carefully read the installation notes in the README file before installation. 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, if sites had previously removed the setuid permissions for the eject program, they would not have been susceptible to this latest vulnerability. - - - ---------------------------------------------------------------------------- [ End AUSCERT Advisories ] ______________________________________________________________________________ CIAC wishes to acknowledge the contributions of AUSCERT 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 Majordomo, 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: E-mail to ciac-listproc@llnl.gov or majordomo@tholia.llnl.gov: subscribe list-name e.g., subscribe ciac-notes You will receive an acknowledgment email immediately with a confirmation that you will need to mail back to the addresses above, as per the instructions in the email. This is a partial protection to make sure you are really the one who asked to be signed up for the list in question. If you include the word 'help' in the body of an email to the above address, it will also send back an information file on how to subscribe/unsubscribe, get past issues of CIAC bulletins via email, etc. 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-51: Vulnerability in libXt H-52: IRIX csetup Program Vulnerability H-53: Vulnerability in webdist.cgi H-54: Vulnerability in xlock H-55: IRIX netprint Program Security Vulnerability H-56: Solaris 2.x lp temporary files creation Vulnerability H-57: Windows NT/95 Out of Band Data Exploit H-58: IRIX runpriv Program Vulnerability H-59: Solaris 2.x ps Buffer Overflow Vulnerability H-60: Vulnerability in metamail ========================FORWARDED TEXT ENDS HERE============================= The National Institute of Standards and Technology (NIST) has established a Federal Computer Incident response Capability (FedCIRC) to assist federal civilians agencies in their incident handling efforts by providing proactive and reactive computer security related services. FedCIRC is a partnership among NIST, the Computer Incident Advisory Capability (CIAC), and the CERT* Coordination Center (CERT/CC). If you believe that your system has been compromised, please contact FedCIRC: Telephone: +1 888 282 0870 Email: fedcirc@fedcirc.gov Web Server: http://www.fedcirc.gov/ * Registered in U.S. Patent and Trademark Office The CERT Coordination Center is part of the Software Engineering Institute. The Software Engineering Institute is sponsored by the U.S. Department of Defense. 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. 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. -----BEGIN PGP SIGNATURE----- Version: 2.6.2 Comment: Processed by Mailcrypt 3.3, an Emacs/PGP interface iQCVAwUBM6WFdXVP+x0t4w7BAQGXjwP9EOUS9Dxa3DevHUJ3h2z6/XB4gLJBOb4L mMFpZAEdvBoYM0woZ0m2o7s/tbC8H/JjMlr9wqwNvmDkHYK4BdAXQjXDnXuukKAu x3CJwfzxlTApVmhmzc0VJNw6VwH46+km4y+T8h6nywOexpz4s84B3408l9+zq4eP R3ThnvUKSL8= =Kmhf -----END PGP SIGNATURE-----