-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN SGI IRIX login LOCKOUT parameter Vulnerability May 29, 1997 19:00 GMT Number H-64 ______________________________________________________________________________ PROBLEM: A vulnerability has been identified in the login program when the LOCKOUT parameter in /etc/default/login is set to a number greater than zero. PLATFORM: All SGI systems running IRIX 5.3 and 6.2. Other versions of IRIX may also be vulnerable. DAMAGE: This vulnerability may allow users to create arbitrary or corrupt certain files on the system. SOLUTION: Until patches are available, apply the workaround indicated below. ______________________________________________________________________________ VULNERABILITY Exploit information involving this vulnerability has been made ASSESSMENT: publicly available. ______________________________________________________________________________ [ Start AUSCERT Advisory ] =========================================================================== AA-97.12 AUSCERT Advisory SGI IRIX login LOCKOUT parameter Vulnerability 10 April 1997 Last Revised: -- - ----------------------------------------------------------------------------- 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. [ End AUSCERT Advisory ] ______________________________________________________________________________ CIAC wishes to acknowledge the contributions of AUSCERT, Silicon Graphics Inc., and Alan J Rosenthal from The University of Toronto 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. 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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. 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