-----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 to CERT-NL information contained in this advisory are therefore outdated.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 : Teun Nijssen Index : S-97-53 Distribution : World Page : 1 Classification: External Version: 1 Subject : SGI IRIX 5.0/6.4 xlock buffer overflow Date : 08-Jul-97 =============================================================================== By courtesy of Silicon Graphics we received information on a vulnerability in its xlock implementation. Note that advisory S-97-32 dated 08-may-1997 was about the same problem. This advisory gives SGI patch information. CERT-NL recommends to apply the relevant patches; better two months late than too late. ============================================================================== Silicon Graphics Inc. Security Advisory Title: xlock Vulnerability Number: 19970502-02-PX Date: July 7, 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 Silicon Graphics 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. ______________________________________________________________________________ ----------------------- --- Issue Specifics --- ----------------------- The xlock(1) program is used to lock the local X display of a system until a correct password is entered at the keyboard. The program is setuid root and as part of the process of locking an X display accepts user arguments to establish specific xlock operation. It has been determined that an appropriately crafted set of arguments could be input to the xlock program allowing execution of arbitrary user commands with root privileges. This resulting buffer overflow condition is considered a security vulnerability in the xlock program. 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 SGI systems. This issue will be corrected in future releases of IRIX. -------------- --- Impact --- -------------- The xlock program (/usr/bin/X11/xlock) is installed on all IRIX systems by default. A local account is required in order to exploit this vulnerability both locally and remotely. This vulnerability can be utilized to execute commands with root privileges. This vulnerability has been publically discussed and reported in CERT advisory CA-97.13 and AUSCERT advisory AA-97.24. -------------------------- --- Temporary Solution --- -------------------------- Although patches are available for this issue, it is realized that there may be situations where installing the patches immediately may not be possible. The steps below can be used to remove the vulnerability by removing the permissions of the xlock program. 1) Become the root user on the system. % /bin/su - Password: # 2) Change the permissions on the xlock program. # /bin/chmod 500 /usr/bin/X11/xlock ************ *** NOTE *** ************ Removing the setuid root permissions from the xlock program will prevent non-root users from using the xlock to lock their terminal. 3) Return to previous level. # exit $ ---------------- --- Solution --- ---------------- OS Version Vulnerable? Patch # Other Actions ---------- ----------- ------- ------------- IRIX 3.x no IRIX 4.x no IRIX 5.0.x yes not avail Note 1 IRIX 5.1.x yes not avail Note 1 IRIX 5.2 yes not avail Note 1 IRIX 5.3 yes 2090 IRIX 6.0.x yes not avail Note 1 IRIX 6.1 yes not avail Note 1 IRIX 6.2 yes 2090 IRIX 6.3 yes 2090 IRIX 6.4 yes 2091 NOTES 1) upgrade operating system or see "Temporary Solution" section. Patches are available via anonymous FTP and your service/support provider. The SGI anonymous FTP site is sgigate.sgi.com (204.94.209.1) or its mirror, ftp.sgi.com. Security information and patches can be found in the ~ftp/security and ~ftp/patches directories, respectfully. ##### Patch File Checksums #### The actual patch will be a tar file containing the following files: Filename: README.patch.2090 Algorithm #1 (sum -r): 50124 8 README.patch.2090 Algorithm #2 (sum): 49453 8 README.patch.2090 MD5 checksum: 4D51EA09250113215760C045BE8F5E14 Filename: patchSG0002090 Algorithm #1 (sum -r): 49562 1 patchSG0002090 Algorithm #2 (sum): 25201 1 patchSG0002090 MD5 checksum: 99F72D8E24773A63306A0118F56411E7 Filename: patchSG0002090.idb Algorithm #1 (sum -r): 47573 1 patchSG0002090.idb Algorithm #2 (sum): 35831 1 patchSG0002090.idb MD5 checksum: 9E16916C33EA81D2C090A9162FB7B099 Filename: patchSG0002090.x_eoe_sw Algorithm #1 (sum -r): 40887 114 patchSG0002090.x_eoe_sw Algorithm #2 (sum): 62640 114 patchSG0002090.x_eoe_sw MD5 checksum: 7088ECF05104E049DCC1D5150EE41F8C Filename: README.patch.2091 Algorithm #1 (sum -r): 08547 8 README.patch.2091 Algorithm #2 (sum): 35395 8 README.patch.2091 MD5 checksum: 54836F64E12DDBAE09E1F165B42A7B01 Filename: patchSG0002091 Algorithm #1 (sum -r): 50655 1 patchSG0002091 Algorithm #2 (sum): 27369 1 patchSG0002091 MD5 checksum: 857AE0806FE273DB75F99264873828FD Filename: patchSG0002091.idb Algorithm #1 (sum -r): 07183 1 patchSG0002091.idb Algorithm #2 (sum): 35505 1 patchSG0002091.idb MD5 checksum: 134D7A6DC774425B6CC73A84A9468833 Filename: patchSG0002091.x_eoe_sw Algorithm #1 (sum -r): 23378 102 patchSG0002091.x_eoe_sw Algorithm #2 (sum): 26001 102 patchSG0002091.x_eoe_sw MD5 checksum: 1FF45DAC2F7FDCCAB8A982ED77554DDA ------------------------ --- Acknowledgments --- ------------------------ Silicon Graphics Inc. wishes to thank the CERT Coordination Center and AUSCERT for their assistance in this issue. ============================================================================== CERT-NL is the Computer Emergency Response Team for SURFnet customers. 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