-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN SGI IRIX fsdump Vulnerability March 11, 1997 19:00 GMT Number H-39 ______________________________________________________________________________ PROBLEM: A vulnerability exists in the fsdump program used in the rfind Server Utilities. PLATFORM: All SGI systems running IRIX 5.x and 6.x DAMAGE: This vulnerability may allow local users to gain root privileges. SOLUTION: Until patches are available, follow the solution outlined below. ______________________________________________________________________________ VULNERABILITY Exploit details involving this vulnerability have been made ASSESSMENT: publicly available. ______________________________________________________________________________ [ Start SGI Advisory ] ______________________________________________________________________________ Silicon Graphics Inc. Security Advisory Title: IRIX 5.x and 6.x fsdump Security Number: 19970301-01-P Date: March 10, 1997 ______________________________________________________________________________ Silicon Graphics provides this information freely to the SGI user community for its consideration, interpretation, implementation and use. Silicon Graphics recommends that this information be acted upon as soon as possible. Silicon Graphics provides the information in this Security Advisory on an "AS-IS" basis only, and disclaims all warranties with respect thereto, express, implied or otherwise, including, without limitation, any warranty of merchantability or fitness for a particular purpose. In no event shall SGI be liable for any loss of profits, loss of business, loss of data or for any indirect, special, exemplary, incidental or consequential damages of any kind arising from your use of, failure to use or improper use of any of the instructions or information in this Security Advisory. ______________________________________________________________________________ - -------------------- - ---- Description --- - -------------------- A security vulnerability has been found with the fsdump program used in the rfind Server Utilities, in the optionally installed subsystem eoe.sw.rfindd (IRIX 6.2) or eoe2.sw.rfindd (IRIX releases prior to 6.2). Silicon Graphics Inc. has investigated the issue and recommends the following steps for neutralizing the exposure. It is HIGHLY RECOMMENDED that these measures be implemented on ALL vulnerable SGI systems running IRIX versions 5.x, 6.0.x, 6.1, and 6.2. This issue has been corrected in more recent releases of IRIX and will be corrected in future releases of IRIX. - --------------- - ---- Impact --- - --------------- The fsdump program is found in the eoe.sw.rfindd and eoe2.sw.rfindd subsystems which are not installed by default. As optional subsystems, these packages must be explicitly installed for use. Only systems with the fsdump program present are vulnerable. Root permissions can be obtained on any system which has the /var/rfindd/fsdump program installed with setuid permissions. Exploitation of this vulnerability requires access to an established account on the system. Provided with an established account, the vulnerability can be exploited locally or remotely. This issue has been publically disclosed in several public forums including the BUGTRAQ mailing list. - ----------------- - ---- Solution --- - ----------------- The solution to this problem is to remove the setuid bit on the fsdump program or to remove the rfindd subsystem. To determine if the subsystem containing the fsdump program is installed on a particular system, the following command can be used: % versions -Inv | grep rfindd I eoe.sw.rfindd 1233007732 rfind Server Utilities In the above case, the optional subsystem containing the fsdump software is installed and the steps in the section titled "**** IRIX 5.x, 6.0, 6.0.1, 6.1, 6.2 ****" should be performed. If no output is returned then the subsystem is not installed but existence of the program should be double checked with the following command: % ls -al /var/rfindd/fsdump /usr/rfindd/fsdump Cannot access /var/rfindd/fsdump: No such file or directory Cannot access /usr/rfindd/fsdump: No such file or directory In the above case, the fsdump program is not found and no further action is required. If a file listing is returned, then the fsdump program is present and the steps below should be performed. **** IRIX 5.x, 6.0, 6.0.1, 6.1, 6.2 **** There are no patches for this issue. The steps below can be used to remove the vulnerability. There are two possible solutions to this issue. Solution A in which the fsdump program permissions are corrected or Solution B in which the rfindd subsystem is removed. Either solution can be used depending on site requirements. Solution A - Change program permissions. 1) Become the root user on the system. % /bin/su - Password: # 2) Move fsdump's cron task from the rfindd crontab file (/var/spool/cron/crontabs/rfindd) to the crontab file for root (/var/spool/cron/crontabs/root) by concatenating the rfind crontab file to the root crontab file. Then move the rfindd crontab file out of the way so it will not be used. # cd /var/spool/cron/crontabs # cat rfindd >> root # mv rfindd rfindd.old.insecure 3) Edit the root crontab file and change the newly added line to execute in the rfindd directory. # vi /var/spool/cron/crontabs/root {Find the newly added fsdump line} 3 0-3,5-23 * * * /etc/chkconfig rfindd && exec ./runfsdump {Add the cd operation to the fsdump line} New entry ----+ | V |-------------| 3 0-3,5-23 * * * cd /var/rfindd; /etc/chkconfig rfindd && exec ./runfsdump {Save the file and exit} 4) Remove the setuid bit from the shipped fsdump program # chmod -s /var/rfindd/fsdump 5) Return to previous level. # exit $ Solution B - Removal of the software. 1) Become the root user on the system. % /bin/su - Password: # 2) Remove the vulnerable subsystems. # /usr/sbin/versions -v remove eoe.sw.rfindd eoe2.sw.rfindd 3) Determine what patches are install on the system. # versions -b | grep patch | cut -c4-20 4) From the patches found in step 3, remove any occurances of the following patches: patchSG0000159 patchSG0000415 patchSG0000528 patchSG0000739 patchSG0000852 patchSG0000159 patchSG0001122 To remove a patch, use the versions command. For example, to remove the patch patchSG0000528: # /usr/sbin/versions -v remove patchSG0000528 5) Return to previous level. # exit $ **** IRIX 6.3 and 6.4 **** The IRIX operating system versions 6.3 and 6.4 do not have this vulnerability and no further action is required. [ End SGI Advisory ] ______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Silicon Graphics Inc. 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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