__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Sun sendmail(1M) ".forward" Constructs Vulnerability [Sun Alert ID: 50904] March 7, 2003 17:00 GMT Number N-050 ______________________________________________________________________________ PROBLEM: A security issue has been discovered with how Sun's sendmail(1M) handles some $HOME/.forward constructs. PLATFORM: SPARC - Solaris 7, 8, and 9 x86 - Solaris 7, 8, and 9 DAMAGE: Local unprivileged users may possibly gain unauthorized root access to their mail server or cause a denial of service to it. SOLUTION: Apply vendor available patches. ______________________________________________________________________________ VULNERABILITY The risk is MEDIUM. There are no reliable symptoms that would ASSESSMENT: show the described issue has been exploited to gain unauthorized root access. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/N-050.shtml ORIGINAL BULLETIN: http://sunsolve.sun.com/pub-cgi/retrieve.pl?doc=fsalert% 2F50904&zone_32=category%3Asecurity ______________________________________________________________________________ [***** Start Sun Alert ID: 50904 *****] Sun(sm) Alert Notification Sun Alert ID: 50904 Synopsis: Sun sendmail(1M) does not Handle Some ".forward" Constructs Correctly Category: Security Product: Solaris BugIDs: 4756570 Avoidance: Patch State: Resolved Date Released: 05-Mar-2003 Date Closed: 05-Mar-2003 Date Modified: 1. Impact Local unprivileged users may be able to cause a denial of service against their mail server or possibly gain unauthorized root access to their mail server due to a security issue with how Sun's sendmail(1M) handles some $HOME/.forward constructs. 2. Contributing Factors This issue can occur in the following releases: SPARC Platform Solaris 7 without patch 107684-06 Solaris 8 without patch 110615-07 Solaris 9 without patch 113575-02 x86 Platform Solaris 7 without patch 107685-06 Solaris 8 without patch 110616-07 Solaris 9 without patch 114137-01 Note: Solaris 2.6 is not impacted by this issue. Solaris 2.5.1 will not be evaluated regarding the potential impact of the issue described in this Sun Alert document. 3. Symptoms There are no reliable symptoms that would show the described issue has been exploited to gain unauthorized root access to a host. The denial of service symptoms would primarily be the inability of local or remote users to login. Solution Summary Top 4. Relief/Workaround To work around the described issue, modify the *.mc file used to generate the /etc/mail/sendmail.cf file by adding the following line in the *.mc file: define(`VENDOR_NAME', `Berkeley')dnl Generate the new /etc/mail/sendmail.cf file from this revised *.mc file and copy this to /etc/mail/sendmail.cf. Please refer to /usr/lib/mail/README for additional information on how to use the *.mc files. Or, edit the /etc/mail/sendmail.cf (not recommended) by changing the following line in the /etc/mail/sendmail.cf file from: V10/Sun to: V10/Berkeley Restart sendmail once the /etc/mail/sendmail.cf file has been modified: # /etc/init.d/sendmail stop # /etc/init.d/sendmail start 5. Resolution This issue is addressed in the following releases: SPARC Platform Solaris 7 with patch 107684-06 or later Solaris 8 with patch 110615-07 or later Solaris 9 with patch 113575-02 or later x86 Platform Solaris 7 with patch 107685-06 or later Solaris 8 with patch 110616-07 or later Solaris 9 with patch 114137-01 or later Note: In order to activate the fix above, restart sendmail once the patches have been installed: # /etc/init.d/sendmail stop # /etc/init.d/sendmail start 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, th! e 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: 50904 *****] _______________________________________________________________________________ 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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