=========================================================================== CA-92:12 CERT Advisory May 28, 1992 Revised Patch for SunOS /usr/etc/rpc.mountd Vulnerability --------------------------------------------------------------------------- *** THIS IS A REVISED CERT ADVISORY *** *** IT CONTAINS NEW VULNERABILITY AND PATCH INFORMATION *** *** SUPERSEDES CERT ADVISORY CA-91:09 *** The Computer Emergency Response Team/Coordination Center (CERT/CC) has received information concerning the availability of a revised security patch for /usr/etc/rpc.mountd in Sun Microsystems Computer Corporation operating systems. This patch fixes an additional vulnerability that was not addressed in CERT advisory CA-91:09.SunOS.rpc.mountd.vulnerability. Sun has provided patches for SunOS 4.1, SunOS 4.1_PSR_A, SunOS 4.1.1, and SunOS 4.1.2. These patches are available through your local Sun Answer Center as well as through anonymous ftp from ftp.uu.net (137.39.1.9) in the /systems/sun/sun-dist directory. Patch ID and file information are as follows: Fix Patch ID Filename Checksum /usr/etc/rpc.mountd 100296-02 100296-02.tar.Z 30606 23 Please note that Sun Microsystems sometimes updates patch files. If you find that the checksum is different, please contact Sun Microsystems or the CERT/CC for verification. --------------------------------------------------------------------------- I. Description Under certain conditions an exported NFS filesystem can be mounted by any system on the Internet even though it may appear that access to the filesystem is restricted to specific hosts. II. Impact Unauthorized remote hosts will be able to mount the exported filesystem. III. Solution As root: 1. Move the existing rpc.mountd aside and change the permissions. # mv /usr/etc/rpc.mountd /usr/etc/rpc.mountd.OLD # chmod 400 /usr/etc/rpc.mountd.OLD 2. Install the new version # cp `arch`/rpc.mountd /usr/etc # chown root.staff /usr/etc/rpc.mountd # chmod 755 /usr/etc/rpc.mountd 3. Kill the currently running rpc.mountd and restart it, or reboot the system. In either case, systems with filesystems mounted from this host will have interruptions in service. --------------------------------------------------------------------------- If you believe that your system has been compromised, contact CERT/CC or your representative in FIRST (Forum of Incident Response and Security Teams). Internet E-mail: cert@cert.org Telephone: 412-268-7090 (24-hour hotline) CERT/CC personnel answer 7:30 a.m.-6:00 p.m. EST(GMT-5)/EDT(GMT-4), on call for emergencies during other hours. Computer Emergency Response Team/Coordination Center (CERT/CC) Software Engineering Institute Carnegie Mellon University Pittsburgh, PA 15213-3890 Past advisories, information about FIRST representatives, and other information related to computer security are available for anonymous ftp from cert.org (192.88.209.5).