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                                @stake, Inc.
                              www.atstake.com

                             Security Advisory

Advisory Name: Long argv[] buffer overflow
 Release Date: 10/28/2003
  Application: Mac OS X
     Platform: Mac OS X (10.2.8 and below)
     Severity: attackers can crash Mac OS X and possibly execute
               commands as root
       Author: Matt Miller <mpmiller@mac.com>
               Dave G. <daveg@atstake.com>
Vendor Status: Vendor has fixed release available
CVE Candidate: CAN-2003-0895
    Reference: www.atstake.com/research/advisories/2003/a102803-3.txt


Overview:

It is possible to cause the the Mac OS X kernel to crash by specifying
a long command line argument.  While this primarily affects local
users there may be conditions where this situation is remotely
exploitable if a program which receives network input spawns another
process with user input.  It is possible to use this condition to
dump small portions of memory back to an attacker. 

      
Details: 

It is possible to cause the Mac OS X kernel to crash by specifying
a long command line argument.  The length of the total arguments must
be within a narrow range to cause this condition.  When it occurs, the
operating system will immediately crash, not allowing users to perform
any task.  No logs will be generated, nor will a kernel panic message
be displayed.  The machine will reboot on its own after several
minutes. 

It is also possible to use this condition to dump small portions of
memory back to an attacker.  As far as @stake can tell, only memory
addresses are being returned back to the user, which is typically
not sensitive data.

@stake has not fully investigated the exploitability of this attack
but since it appears to be an overflow in the kernel the severity
of "possibly execute commands as root" is warranted.


Vendor Response:

Kernel: Fixes CAN-2003-0895 where it may be possible for a local user
to cause the Mac OS X kernel to crash by specifying a long command
line argument. The machine will reboot on its own after several
minutes.

 This is fixed in Mac OS X 10.3. For further information on Mac
 OS X 10.3, please see http://www.apple.com/macosx/


Recommendation:

Upgrade to Panther (Mac OS X 10.3)


Common Vulnerabilities and Exposures (CVE) Information:

The Common Vulnerabilities and Exposures (CVE) project has assigned
the following names to these issues.  These are candidates for
inclusion in the CVE list (http://cve.mitre.org), which standardizes
names for security problems.

 CAN-2003-0895 Long argv[] buffer overflow
 

@stake Vulnerability Reporting Policy:
http://www.atstake.com/research/policy/

@stake Advisory Archive:
http://www.atstake.com/research/advisories/

PGP Key:
http://www.atstake.com/research/pgp_key.asc

@stake is currently seeking application security experts to fill
several consulting positions.  Applicants should have strong
application development skills and be able to perform application
security design reviews, code reviews, and application penetration
testing.  Please send resumes to jobs@atstake.com.

Copyright 2003 @stake, Inc. All rights reserved.


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