Published:
08 July 1997
Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-97.080 -- SGI Security Advisory 19970502-02-PX xlock Program Vulnerability 9 July 1997 Last Revised: 10 July 1997 Changed header to include the correct ESB release date. A complete revision history is at the end of this file. =========================================================================== Silicon Grahpics has released the following advisory concerning a vulnerability in the xlock program. This vulnerability may allow local users to gain root privileges. This bulletin addresses vulnerabilities previously described in AUSCERT Advisory AA-97.24 (SGI IRIX xlock Buffer Overrun Vulnerability) and CERT/CC Advisory CA-97.13 re-released by AUSCERT as ESB-97.059. The following security bulletin is provided as a service to AUSCERT's members. As AUSCERT did not write this document, AUSCERT has had no control over its content. As such, the decision to use any or all of this information is the responsibility of each user or organisation, and should be done so in accordance with site policies and procedures. Contact information for Silicon Graphics is included in the Security Bulletin below. If you have any questions or need further information, please contact them directly. If you believe that your system has been compromised, contact AUSCERT or your representative in FIRST (Forum of Incident Response and Security Teams). Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 4477 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AUSCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for emergencies. - ---------------------------BEGIN INCLUDED TEXT------------------------ - -----BEGIN PGP SIGNED MESSAGE----- ______________________________________________________________________________ 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. - - ----------------------------------------------------------- - - --- Silicon Graphics Inc. Security Information/Contacts --- - - ----------------------------------------------------------- If there are questions about this document, email can be sent to cse-security-alert@sgi.com. ------oOo------ Silicon Graphics provides security information and patches for use by the entire SGI community. This information is freely available to any person needing the information and is available via anonymous FTP and the Web. The primary SGI anonymous FTP site for security information and patches is sgigate.sgi.com (204.94.209.1). Security information and patches are located under the directories ~ftp/security and ~ftp/patches, respectively. The Silicon Graphics Security Headquarters Web page is accessible at the URL http://www.sgi.com/Support/Secur/security.html. For issues with the patches on the FTP sites, email can be sent to cse-security-alert@sgi.com. For assistance obtaining or working with security patches, please contact your SGI support provider. ------oOo------ Silicon Graphics provides a free security mailing list service called wiretap and encourages interested parties to self-subscribe to receive (via email) all SGI Security Advisories when they are released. Subscribing to the mailing list can be done via the Web (http://www.sgi.com/Support/Secur/wiretap.html) or by sending email to SGI as outlined below. % mail wiretap-request@sgi.com subscribe wiretap <YourEmailAddress> end ^d In the example above, <YourEmailAddress> is the email address that you wish the mailing list information sent to. The word end must be on a separate line to indicate the end of the body of the message. The control-d (^d) is used to indicate to the mail program that you are finished composing the mail message. ------oOo------ Silicon Graphics provides a comprehensive customer World Wide Web site. This site is located at http://www.sgi.com/Support/Secur/security.html. ------oOo------ For reporting *NEW* SGI security issues, email can be sent to security-alert@sgi.com or contact your SGI support provider. A support contract is not required for submitting a security report. ______________________________________________________________________________ This information is provided freely to all interested parties and may be redistributed provided that it is not altered in any way, Silicon Graphics is appropriately credited and the document retains and includes its valid PGP signature. - -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQCVAwUBM8FvdLQ4cFApAP75AQFUeQQAkSGeKlM8xVnrnkxffodmCYKm5DP5SGCU mfRiIvi9i2tuuzOGNNDGo7d5DE2xhL+40yfoNUTNBvCpj5Oz5KHUyWU93kfQGB3c f3JgsEcc8s888cOqTRenqhqP6Ey0+tjJItsRC5oo+hharJTAcmTBh9BRBHm5I5UL ngmPNnHE3pE= =rLt0 - -----END PGP SIGNATURE----- - -----------------------------END INCLUDED TEXT-------------------------------- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Revision History 10 Jul, 1997 Corrected the ESB release date in the header. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -----BEGIN PGP SIGNATURE----- Version: 2.6.3i Charset: noconv Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key iQCVAwUBM8TTjCh9+71yA2DNAQHeXgP/f12v4aYqoNbWmMCeaVSjuFOqCapAKa3m +/pBX4Uj0OZ8fJznGSyP9Zf3bEXtmow/AquRMmqZuIxaJBieAgJ7Tdi7Cfz+hy8a /kV+EU7nZ/jfgRKMBxrLtp99/nn/4FQU4S/j+spR+c1pm/WpYOQZf8daXI7CaotQ 6EyJMlkJeqM= =xQFt -----END PGP SIGNATURE-----