home *** CD-ROM | disk | FTP | other *** search
- ===========================================================================
- CA-92:04 CERT Advisory
- February 25, 1992
- AT&T /usr/etc/rexecd Vulnerability
-
- ---------------------------------------------------------------------------
-
- The Computer Emergency Response Team/Coordination Center (CERT/CC) has
- received information concerning a vulnerability in AT&T TCP/IP Release
- 4.0 running on SVR4 systems for both the 386/486 and 3B2 RISC platforms.
-
- The existing error, in the remote execution server /usr/etc/rexecd, has
- been corrected, and a new executable for rexecd is available from AT&T
- by calling 800-543-9935. Patches may be obtained outside the U.S. by
- calling your local technical support. The numbers associated with the
- fix are 5127 (3.5" media) and 5128 (5.25" media).
-
- The problem does not exist in TCP/IP release 3.2 for SVR3, or any earlier
- versions of the TCP/IP product running on either the 3B2 or 386 platforms.
-
- The version of TCP/IP distributed with SVR4 by UNIX(r) System Laboratories,
- Inc. (a subsidiary of AT&T) does not contain this vulnerability.
-
- UNIX(r) is a registered trademark of UNIX System Laboratories, Inc.
-
- ---------------------------------------------------------------------------
-
- I. Description
-
- A vulnerability has been identified where root privileges may be
- accessed through the use of /usr/etc/rexecd.
-
- II. Impact
-
- A user on a remote machine may be able to run commands as root on
- the target host (the host running the affected /usr/etc/rexecd).
-
- III. Solution
-
- 1. Administrators of affected systems should execute, as root, the
- following command to immediately turn off access to rexecd until
- the new binary can be obtained.
-
- # chmod 400 /usr/etc/rexecd
-
- 2. Obtain and install the new patch. The fix will be supplied as
- one diskette, and it comes with one page of instructions documenting
- the procedure to replace the existing /usr/etc/rexecd binary.
-
- ---------------------------------------------------------------------------
- The CERT/CC wishes to thank Bradley E. Smith, Network & Technical Services,
- Bradley University, for bringing this vulnerability to our attention and for
- providing a corresponding solution. We would also like to thank AT&T for
- their very quick response to this problem.
- ---------------------------------------------------------------------------
-
- 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.sei.cmu.edu
- 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.sei.cmu.edu (192.88.209.5).
-
-