_____________________________________________________ The Computer Incident Advisory Capability ___ __ __ _ ___ / | / \ / \___ __|__ /___\ \___ _____________________________________________________ ADVISORY NOTICE Vulnerability in SunOS expreserve Utility June 11, 1993 0001 PDT Number D-16 __________________________________________________________________________ PROBLEM: The expreserve utility allows unauthorized access to system files. PLATFORM: Sun workstations running SunOS versions 4.1, 4.1.1, 4.1.2, 4.1.3, 5.0, 5.1, and 5.2. DAMAGE: Local users can gain root access. SOLUTION: Disable expreserve immediately, then install patch from Sun. __________________________________________________________________________ Critical Information about the expreserve Vulnerability CIAC has learned that the expreserve utility in SunOS versions 4.1, 4.1.1, 4.1.2, 4.1.3, 5.0, 5.1, and 5.2 contains a serious vulnerability that allows any file on the system to be overwritten. This vulnerability can be used to obtain root access to the system. CIAC strongly recommends that the expreserve utility be disabled immediately, and that patched versions be installed as they become available. Sun Microsystems has released patch 101080-01 which corrects the vulnerability in SunOS 4.x systems. CIAC will announce future patches as they become available. Disabling expreserve -------------------- To prevent use of the expreserve utility, execute the following command as root: /bin/chmod a-x /usr/lib/expreserve The expreserve command normally is used to recover vi editor files when vi terminates unexpectedly. Disabling expreserve will disable this recovery feature. Users of vi should be advised of this temporary change and encouraged to save their work frequently. Patching SunOS version 4.x -------------------------- Sun Microsystems has made available a patched version of expreserve for SunOS Versions 4.1, 4.1.1, 4.1.2, and 4.1.3 that corrects this vulnerability. It is available both through your local Sun Answer Center and anonymous ftp. In the U.S., ftp to ftp.uu.net and retrieve the file /systems/sun/sun-dist/101080-01.tar.Z. In Europe, ftp to mcsun.eu.net and retrieve the file /sun/fixes/101080-01.tar.Z. After retrieving the patch, its checksum may be verified using the following command: /bin/sum 101080-01.tar.Z The sum command should return a checksum of 45221 13. Note that Sun Microsystems occasionally updates patch files, resulting in a changed checksum. Should you find that your checksum differs, please contact CIAC or Sun Microsystems for verification before installing the patch. The patch may be extracted using the following commands: /usr/ucb/uncompress 101080-01.tar.Z /bin/tar xvf 101080-01.tar To install the patch on your system, follow the instructions contained in the README file that accompanies the patch. For additional information or assistance, please contact CIAC at (510)422-8193/FTS or send E-mail to ciac@llnl.gov. FAX messages to (510)423-8002/FTS. CIAC wishes to acknowledge the contributions of the CERT Coordination Center and Sun Microsystems in the preparation of this bulletin. Previous CIAC bulletins and other information are available via anonymous ftp from irbis.llnl.gov (IP 128.115.19.60). PLEASE NOTE: Many users outside of the DOE and ESnet 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 by sending email to docserver@first.org with an empty subject line and a message body containing the line: send first-contacts. 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, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, 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 nor the University of California, and shall not be used for advertising or product endorsement purposes.