__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Sun Linux Vulnerability in VNC Package may allow local or remote unauthorized access [Sun Alert ID: 56161] September 2, 2003 18:00 GMT Number N-140 [REVISED 18 Apr 2005] ______________________________________________________________________________ PROBLEM: A vulnerability with the VNC DES authentication scheme implementation may allow a local or remote unpriviledged user to gain unauthorized access to the system. PLATFORM: Sun Linux 5.0 DAMAGE: The intruder can gain access to the cookie and gain access to the system. SOLUTION: Apply patches as stated in Sun's Security Notification. ______________________________________________________________________________ VULNERABILITY The risk is MEDIUM. An unauthorized user could break into the ASSESSMENT: encrypted channel and take over the system. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/n-140.shtml ORIGINAL BULLETIN: http://www.sunsolve.sun.com/pub-cgi/retrieve.pl?doc= fsalert%2F56161&zone_32=category%3Asecurity ______________________________________________________________________________ REVISION HISTORY: 04/18/2005 - revised N-140 to reflect the changes Sun Microsystems has made to Sun Alert ID: 56161 where they set State to Resolved. [***** Start Sun Alert ID: 56161 *****] Sun(sm) Alert Notification Sun Alert ID: 56161 Synopsis: Sun Linux Vulnerability in VNC Package May Allow Local or Remote Unauthorized Access Category: Security Product: Sun Linux BugIDs: 4892275 Avoidance: Patch, Workaround State: Resolved Date Released: 19-Aug-2003 Date Closed: 13-Apr-2005 Date Modified: 13-Apr-2005 1. Impact A vulnerability with the VNC DES authentication scheme implementation may allow a local or remote unprivileged user to gain unauthorized access to the system. The script for starting the VNC server generates a cookie (which is used for X authentication) without using a sufficiently strong random number generator. Note: VNC is a tool for providing a remote graphical user interface. More information on this issue is available at: Red Hat Advisory RHSA-2003:041-15 at: https://rhn.redhat.com/errata/ RHSA-2003-041.html CVE CAN-2002-1511 at: http://cve.mitre.org/cgi-bin/cvename.cgi?name= CAN-2002-1511 CVE CAN-2002-1336 at: http://cve.mitre.org/cgi-bin/cvename.cgi?name= CAN-2002-1336 2. Contributing Factors This issue can occur in the following releases: Sun Linux Sun Linux 5.0 (LX50) with VNC versions 3.3.3r2-18.4 or earlier Notes: Sun Linux 5.0 is currently shipped with the Sun LX50 Server. The VNC package version can be determined by running the following command: $ rpm -qa | grep -i vnc vnc-3.3.3r2-18.4 3. Symptoms There are no predictable symptoms that would indicate the described issue has been exploited. Solution Summary Top 4. Relief/Workaround To work around the described issue until patches can be applied, temporarily disable VNC with the following steps: 1. To see if VNC is enabled (displayed at all run levels), use the following command: # /sbin/chkconfig --list vncserver vncserver 0:off 1:off 2:off 3:on 4:on 5:on 6:off 2. Disable VNC for all run levels with the following command: # /sbin/chkconfig --del vncserver 5. Resolution Sun Linux patches are available at: http://sunsolve.sun.com/patches/ linux/security.html Change History 13-Apr-2005: * Set State to Resolved This Sun Alert notification is being provided to you on an "AS IS" basis. This Sun Alert notification may contain information provided by third parties. The issues described in this Sun Alert notification may or may not impact your system(s). Sun makes no representations, warranties, or guarantees as to the information contained herein. ANY AND ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT, ARE HEREBY DISCLAIMED. BY ACCESSING THIS DOCUMENT YOU ACKNOWLEDGE THAT SUN SHALL IN NO EVENT BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES THAT ARISE OUT OF YOUR USE OR FAILURE TO USE THE INFORMATION CONTAINED HEREIN. This Sun Alert notification contains Sun proprietary and confidential information. It is being provided to you pursuant to the provisions of your agreement to purchase services from Sun, or, if you do not have such an agreement, the Sun.com Terms of Use. This Sun Alert notification may only be used for the purposes contemplated by these agreements. Copyright 2000-2003 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, CA 95054 U.S.A. All rights reserved. [***** End Sun Alert ID: 56161 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Sun Microsystems 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. CIAC can be contacted at: Voice: +1 925-422-8193 (7x24) FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@ciac.org Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ Anonymous FTP: ftp.ciac.org PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. 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. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. 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