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CA-91:23

Last Revised: September 18,1997

                Attached copyright statement            



                               CERT Advisory

                             December 18, 1991

            Hewlett Packard/Apollo Domain/OS crp Vulnerability

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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.



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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.



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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.org

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.org (192.88.209.5) system.



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Copyright 1991 Carnegie Mellon University. Conditions for use, disclaimers,

and sponsorship information can be found in

http://www.cert.org/legal_stuff.html and http://ftp.cert.org/pub/legal_stuff .

If you do not have FTP or web access, send mail to cert@cert.org with

"copyright" in the subject line.



CERT is registered in the U.S. Patent and Trademark Office.



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Revision History



September 18,1997  Attached Copyright Statement





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