_____________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | / \ / \___ __|__ /___\ \___ _____________________________________________________ INFORMATION BULLETIN Solaris System Startup Vulnerability December 17, 1993 1500 PST Number E-06 ______________________________________________________________________________ PROBLEM: Solaris system startup vulnerability. PLATFORM: Solaris 2.x and Solaris x86 systems. DAMAGE: Anyone with physical access to a workstation with eeprom(1m) security enabled may gain root level privilege without supplying the eeprom or root password. SOLUTION: Change system scripts as described or restrict physical access. ______________________________________________________________________________ Critical Information about the Solaris System Startup Vulnerability CIAC has received information from Sun Microsystems regarding a security vulnerability in the Solaris system 2.x and x86 startups. This vulnerability allows a person with physical access to a workstation with eeprom(1m) security enabled to force a startup failure and subsequently gain root privilege without supplying the eeprom or root password. Changing the system scripts as described below or restricting physical access to the workstations will eliminate this vulnerability. Note that without eeprom security enabled, a workstation is vulnerable to any unauthorized individual who has physical access. Without the script changes, if fsck(8) fails during boot, the system will run a privileged shell on the workstation. Since an attacker can force the failure, CIAC recommends application of the changes described below. If this is not possible, then restrict physical workstation access to only those users allowed root privilege. The changes will require the user to enter the root password before the system runs the privileged shell. To make the changes, edit both /sbin/rcS and /sbin/mountall. Change every occurrence of /sbin/sh < /dev/console to /sbin/sulogin < /dev/console The Sun distribution of /sbin/rcS contains an occurrence of the target string at line 152; the distribution of /sbin/mountall contains one at line 66 and one at line 250. An attacker with physical access to a workstation without eeprom security enabled can easily compromise the system by booting it in single user mode. CIAC thus recommends enabling eeprom security for all workstations without strict physical access controls. ______________________________________________________________________________ CIAC wishes to thank Sun Microsystems for first bringing the vulnerability to our attention, and both Sun Microsystems and the CERT Coordination Center for portions of the information in this bulletin. ______________________________________________________________________________ For additional information or assistance, please contact CIAC: Voice: (510) 422-8193 FAX: (510) 423-8002 STU-III: (510) 423-2604 E-mail: ciac@llnl.gov Previous CIAC Bulletins and other information are available via anonymous FTP from irbis.llnl.gov (IP address 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.