*********************************************************************** DDN Security Bulletin 9106 DCA DDN Defense Communications System 1 May 91 Published by: DDN Security Coordination Center (SCC@NIC.DDN.MIL) (800) 235-3155 DEFENSE DATA NETWORK SECURITY BULLETIN The DDN SECURITY BULLETIN is distributed by the DDN SCC (Security Coordination Center) under DCA contract as a means of communicating information on network and host security exposures, fixes, & concerns to security & management personnel at DDN facilities. Back issues may be obtained via FTP (or Kermit) from NIC.DDN.MIL [192.67.67.20] using login="anonymous" and password="guest". The bulletin pathname is SCC:DDN-SECURITY-yynn (where "yy" is the year the bulletin is issued and "nn" is a bulletin number, e.g. SCC:DDN-SECURITY-9001). ********************************************************************** DEC Ultrix chroot Vulnerability + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + ! ! ! The following important advisory was issued by the Computer ! ! Emergency Response Team (CERT) and is being relayed unedited ! ! via the Defense Communications Agency's Security Coordination ! ! Center distribution system as a means of providing DDN ! ! subscribers with useful security information. ! ! ! + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + CA-91:05 CERT Advisory May 1, 1991 DEC Ultrix chroot Vulnerability --------------------------------------------------------------------------- The Computer Emergency Response Team/Coordination Center (CERT/CC) has received information concerning a vulnerability in Digital Equipment Corporation's (DEC) Ultrix operating system versions 4.0 and 4.1 for all DEC architectures. The vulnerability has been fixed in version 4.2 which will be shipped beginning in late May. DEC has also provided a suggested fix for versions 4.0 and 4.1. --------------------------------------------------------------------------- I. DESCRIPTION: By default, /usr/bin/chroot is improperly installed in Ultrix versions 4.0 and 4.1. II. IMPACT: System users can gain unauthorized privileges. III. SOLUTION: Change the permission on the file /usr/bin/chroot. # chmod 700 /usr/bin/chroot --------------------------------------------------------------------------- Our thanks to Eric R. Jorgensen and Brian Ellis of UnixOps / Distributed Computing Services at the University of Colorado, Boulder, for bringing this problem to our attention. The CERT/CC would also like to thank Digital for their response to this vulnerability. --------------------------------------------------------------------------- If you believe that your system has been compromised, contact CERT/CC via telephone or e-mail. Computer Emergency Response Team/Coordination Center (CERT/CC) Software Engineering Institute Carnegie Mellon University Pittsburgh, PA 15213-3890 Internet E-mail: cert@cert.sei.cmu.edu Telephone: 412-268-7090 24-hour hotline: CERT/CC personnel answer 7:30a.m.-6:00p.m. EST, on call for emergencies during other hours. Past advisories and other computer security related information are available for anonymous ftp from the cert.sei.cmu.edu (128.237.253.5) system. Organization: National Institute of Standards and Technology (NIST) Sub-Organization: National Computer Systems Laboratory