CERT Advisory 036

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CERT Advisory

 · 4 years ago

  

 
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CA-91:23                       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. 
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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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