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CA-91:16                        CERT Advisory
                              September 18, 1991
                    SunOS SPARC Integer Division Vulnerability

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The Computer Emergency Response Team/Coordination Center (CERT/CC) has
received information concerning a vulnerability in Sun Microsystems,
Inc. (Sun) integer division on their SPARC architecture.  This vulner-
ability exists on all SPARC platforms (including sun4 and sun4c)
for SunOS versions 4.1 and 4.1.1.

Sun has provided patches for this vulnerability. They are available through
your local Sun Answer Centers worldwide as well as through anonymous
ftp from the ftp.uu.net system (in the sun-dist directory).  

Fix                        Patch ID       Filename            Checksum
/sys/sun{4,4c}/OBJ/crt.o   100376-01      100376-01.tar.Z     09989    11

Please note that Sun Microsystems sometimes updates patch files.  If
you find that the checksum is different please contact Sun Microsystems
or us for verification.
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I.   Description

     A security vulnerability exists in the integer division
     on the SPARC architecture that can be used to gain root
     privileges.
     
II.  Impact

     Any user logged into the system can gain root access.

III. Solution 
        
     Replace /sys/sun{4,4c}/OBJ/crt.o and rebuild the kernel(s)
     necessary for your host configuration(s).  Reboot each host
     using the appropriate kernel.

     Please refer to the System and Network Administration
     Manual for instructions on building and configuring a
     new custom kernel.

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The CERT/CC wishes to thank Gordon Irlam of the Department of Computer,
University of Adelaide, Australia, for bringing this vulnerability to
our attention and for his further assistance with the solution.  We
also wish to thank Sun Microsystems for their prompt response to this 
vulnerability.
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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.org
Telephone: 412-268-7090 24-hour hotline:
           CERT/CC personnel answer 7:30a.m.-6:00p.m. EDT,
           on call for emergencies during other hours.

Past advisories and other computer security related information are available
for anonymous ftp from the cert.org (192.88.209.5) system.
