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************************************************************************** Security Bulletin 9127 DISA Defense Communications System 19 December 1991 Published by: DDN Security Coordination Center (SCC@NIC.DDN.MIL) 1-(800) 365-3642 DEFENSE DATA NETWORK SECURITY BULLETIN The DDN SECURITY BULLETIN is distributed by the DDN SCC (Security Coordination Center) under DISA 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 [192.112.36.5] 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-9127). ************************************************************************** + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + ! ! ! The following important advisory was issued by the Computer ! ! Emergency Response Team (CERT) and is being relayed unedited ! ! via the Defense Information Systems Agency's Security ! ! Coordination Center distribution system as a means of ! ! providing DDN subscribers with useful security information. ! ! ! + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + =========================================================================== CA-91:23 CERT Advisory December 18, 1991 Hewlett Packard/Apollo Domain/OS crp Vulnerability --------------------------------------------------------------------------- The Computer Emergency Response Team/Coordination Center (CERT/CC) has received information concerning a vulnerability in the crp facility in Hewlett Packard/Apollo Domain/OS. This vulnerability is present on all HP/Apollo Domain/OS SR10 systems up through SR10.3. Patches that address this problem will be available in the SR10.3 patch tape (~Feb 92) and in the SR10.4 software release. Contact your local sales office for more information. --------------------------------------------------------------------------- I. Description There is a security problem with the /usr/apollo/bin/crp facility. A user who is not running crp is not vulnerable to this problem. II. Impact A person at a remote or local site can obtain the privileges of the user who is running crp. III. Workaround The suggested workaround is to disable two system calls that are made by /usr/apollo/bin/crp. The following steps should be executed by root or another appropriate userid that has the privilege to write in the directories involved. 1. Create a file "crplib.c" containing the four-line C program: extern void pad_$dm_cmd(void); void pad_$dm_cmd() { } extern void pad_$def_pfk(void); void pad_$def_pfk() { } 2. Compile this program using '-pic': (AEGIS) /com/cc crplib.c -pic (UNIX) /bin/cc -c crplib.c -W0,-pic 3. Copy the result to somewhere accessible to all users (/lib/crplib is recommended). (AEGIS) /com/cpf crplib.bin /lib/crplib (AEGIS) /com/edacl -p root prwx -g wheel rx -w rx /lib/crplib (UNIX) /bin/cp crplib.o /lib/crplib (UNIX) /bin/chmod 755 /lib/crplib 4. a) Ensure that all users do an 'inlib' of that file before running crp. One way to ensure this would be to replace the /usr/apollo/bin/crp command by a shell script that does the inlib. Doing this step will force crp to use the null functions defined in step 1 above. (AEGIS) /com/chn /usr/apollo/bin/crp crp.orig (UNIX) /bin/mv /usr/apollo/bin/crp /usr/apollo/bin/crp.orig b) Create the file /usr/apollo/bin/crp containing the shell script: (AEGIS) #!/com/sh /com/sh -c inlib /lib/crplib ';' /usr/apollo/bin/crp.orig ^* (UNIX) #!/bin/sh inlib /lib/crplib exec /usr/apollo/bin/crp.orig "$@" c) Make this script executable. (AEGIS) /com/edacl -p root prwx -g wheel rx -w rx /usr/apollo/bin/crp (UNIX) /bin/chmod 755 /usr/apollo/bin/crp --------------- NOTE: This workaround will prevent crp from making use of the two system calls; and therefore, it may affect the functionality of various software programs since they will be unable to define programmable function keys, create new windows on the client node, or execute background processes using the Display Manager interface. --------------------------------------------------------------------------- The CERT/CC wishes to thank Paul Szabo of the University of Sydney for bringing this problem to our attention and providing a workaround. We would also like to thank Jim Richardson of the University of Sydney for his assistance and Hewlett Packard/Apollo for their timely response to the report of this vulnerability. --------------------------------------------------------------------------- If you believe that your system has been compromised, contact CERT/CC via telephone or e-mail. 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(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 and other information related to computer security are available for anonymous ftp from the cert.sei.cmu.edu (192.88.209.5) system.