-----BEGIN PGP SIGNED MESSAGE----- ============================================================================= CERT* Advisory CA-97.15 Original issue date: May 28, 1997 Last revised: --- Topic: Vulnerability in SGI login LOCKOUT - ----------------------------------------------------------------------------- The text of this advisory was originally released on April 10, 1997, as AUSCERT Advisory AA-97.12, developed by the Australian Computer Emergency Response Team. To more widely broadcast this information, we are reprinting the AUSCERT advisory here with their permission. Only the contact information at the end has changed: AUSCERT contact information has been replaced with CERT/CC contact information. We will update this advisory as we receive additional information. Look for it in an "Updates" section at the end of the advisory. ============================================================================= AUSCERT has received information that a vulnerability exists in the login program when the LOCKOUT parameter in /etc/default/login is set to a number greater than zero. This vulnerability is known to be present in IRIX 5.3 and 6.2. Other versions of IRIX may also be vulnerable. This vulnerability may allow users to create arbitrary or corrupt certain files on the system. 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 Under the IRIX operating system, there is a file /etc/default/login which contains default security logging configuration options. If the parameter LOCKOUT is included in this file, and is set to a value greater than zero, it causes accounts to be locked after a specified number of consecutive unsuccessful login attempts by the same user. When LOCKOUT is enabled users may be able to create arbitrary or corrupt certain files on the system, due to an inadequate check in the login verification process. Sites can determine if this functionality is enabled by using the command: % grep '^LOCKOUT' /etc/default/login LOCKOUT=3 If the number on the same line as LOCKOUT is greater than zero the vulnerability may be exploited. Information involving this vulnerability has been made publicly available. Silicon Graphics Inc. has informed AUSCERT that they are investigating this vulnerability. 2. Impact Users may create arbitrary or corrupt certain files on the system. 3. Workarounds/Solution AUSCERT recommends that sites prevent the exploitation of this vulnerability 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 Disable the LOCKOUT parameter To prevent the exploitation of the vulnerability described in this advisory, AUSCERT recommends that the functionality provided with the LOCKOUT parameter be disabled. The LOCKOUT parameter can be disabled by editing /etc/default/login and commenting out the line containing the LOCKOUT parameter. The comment character for /etc/default/login is "#". Note that after applying this workaround, accounts will not be automatically locked using the LOCKOUT parameter functionality. - --------------------------------------------------------------------------- AUSCERT thanks to Alan J Rosenthal from The University of Toronto and Silicon Graphics Inc. for their assistance in this matter. - --------------------------------------------------------------------------- =============================================================================== If you believe that your system has been compromised, contact the CERT Coordination Center or your representative in the Forum of Incident Response and Security Teams (see http://www.first.org/team-info/) CERT/CC Contact Information - ---------------------------- Email cert@cert.org Phone +1 412-268-7090 (24-hour hotline) CERT personnel answer 8:30-5:00 p.m. EST(GMT-5) / EDT(GMT-4) and are on call for emergencies during other hours. Fax +1 412-268-6989 Postal address CERT Coordination Center Software Engineering Institute Carnegie Mellon University Pittsburgh PA 15213-3890 USA Using encryption We strongly urge you to encrypt sensitive information sent by email. We can support a shared DES key or PGP. Contact the CERT/CC for more information. Location of CERT PGP key ftp://info.cert.org/pub/CERT_PGP.key Getting security information CERT publications and other security information are available from http://www.cert.org/ ftp://info.cert.org/pub/ CERT advisories and bulletins are also posted on the USENET newsgroup comp.security.announce To be added to our mailing list for advisories and bulletins, send email to cert-advisory-request@cert.org In the subject line, type SUBSCRIBE your-email-address - --------------------------------------------------------------------------- * Registered U.S. Patent and Trademark Office. Copyright 1997 Carnegie Mellon University This material may be reproduced and distributed without permission provided it is used for noncommercial purposes and the copyright statement is included. The CERT Coordination Center is part of the Software Engineering Institute (SEI). The SEI is sponsored by the U.S. Department of Defense. - --------------------------------------------------------------------------- This file: ftp://info.cert.org/pub/cert_advisories/CA-97.15.sgi_login http://www.cert.org click on "CERT Advisories" ========================================================================== UPDATES May 28, 1997 - ------------ After the AUSCERT advisory was published, we received this information from Silicon Graphics: At this time, Silicon Graphics does not have any public information for the login LOCKOUT issue. Silicon Graphics has communicated with CERT and other external security parties and is actively investigating this issue. When more Silicon Graphics information (including any possible patches) is available for release, that information will be released via the SGI security mailing list, wiretap. For subscribing to the wiretap mailing list and other SGI security related information, please refer to the Silicon Graphics Security Headquarters website located at: http://www.sgi.com/Support/Secur/security.html ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Revision history -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQCVAwUBM4wd63VP+x0t4w7BAQEZhQP5Af9yVOVcKpS2rBHpjX2QSIwI7SKPUGAZ FFX8KJX0jG0TWe/AVREP+vc6N/kOxAGZvJwtc6yo4n7pZxhaNFu3H51qXUiNjEfe VX0IK9xk/iV2qrxenIzYnntzyU5cW6lHv2qwwJufy11cQwDq+qeanDLUQ/CPVn5P m+VO5NVnThM= =oAJo -----END PGP SIGNATURE-----