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NSFOCUS SA2003-02: Solaris lpq Stack Buffer Overflow Vulnerability
From: NSFCOSU Security Team <security () nsfocus com>
Date: Mon, 31 Mar 2003 18:07:24 +0800

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NSFOCUS Security Advisory(SA2003-02)

Topic: Solaris lpq Stack Buffer Overflow Vulnerability

Release Date: 2003-3-31 

CVE CAN ID: CAN-2003-0091

Affected system:
===================

Sun Solaris 2.5.1 (SPARC/x86)
Sun Solaris 2.6 (SPARC/x86)
Sun Solaris 7   (SPARC/x86)
                                                               
Summary:
=========

NSFOCUS Security Team has found a buffer overflow vulnerability in lpq, an 
application in Sun Solaris system. Exploiting the vulnerability local 
attackers could gain root privilege.  

Description:
============

lpq, which is used to display the contents in printing queue, is a command 
in SunOS/BSD compatible package.By default suid root bit is set to it. 
Because valid bound check has not been implemented when handling the data 
provided by users, attackers could cause a fixed stack buffer to overflow.
By carefully crafting overflow data attackers could run arbitrary code with 
root privilege. 

Actually /usr/ucb/lpq is a symbol link to /usr/bin/lpstat. lpstat will 
operate according to the program names during the calling. If "lpq", it will
operate in BSD style, or it will operate in System V style. The bsd_queue()
function in lpq will call strcat() to copy the data provided by users to a 
buffer the size of which is fixed. Because the length of the copied data has
not been checked, if an attacker provides a over-long string, he/she will
cause a stack buffer overflow. By overwriting the returning addresses and other
data in the stack, local attackers could gain root privilege. 

Solaris 8/9 uses strlcat() to implement string copy, so it avoids buffer
overflow and therefore is not vulnerable to the issue.  

Workaround:
=============

 NSFOCUS suggests to disable suid root attribute of lpstat(lpq) temporarily:
 # chmod a-s /usr/bin/lpstat

Vendor Status:
==============

2002-12-11  Informed the vendor.
2002-12-13  The vendor confirmed the vulnerability. 
2003-03-31  The vendor released a Sun Alert and patches for this issue. 

The Sun Alert is available at:
http://sunsolve.Sun.COM/pub-cgi/retrieve.pl?doc=fsalert/52443

The patches are:

Solaris 2.6     106235-12
Solaris 2.6_x86 106236-12
Solaris 7       107115-12
Solaris 7_x86   107116-12


Additional Information:
========================

The Common Vulnerabilities and Exposures (CVE) project has assigned the 
name CAN-2003-0091 to this issue. This is a candidate for inclusion in the
CVE list (http://cve.mitre.org), which standardizes names for security 
problems. Candidates may change significantly before they become official 
CVE entries.

DISCLAIMS:
==========
THE INFORMATION PROVIDED IS RELEASED BY NSFOCUS "AS IS" WITHOUT WARRANTY
OF ANY KIND. NSFOCUS DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED,
EXCEPT FOR THE WARRANTIES OF MERCHANTABILITY. IN NO EVENTSHALL NSFOCUS
BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT,
INCIDENTAL,CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES,
EVEN IF NSFOCUS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
DISTRIBUTION OR REPRODUCTION OF THE INFORMATION IS PROVIDED THAT THE
ADVISORY IS NOT MODIFIED IN ANY WAY.

Copyright 1999-2003 NSFOCUS. All Rights Reserved. Terms of use.


NSFOCUS Security Team <security () nsfocus com>
NSFOCUS INFORMATION TECHNOLOGY CO.,LTD
(http://www.nsfocus.com)

PGP Key: http://www.nsfocus.com/homepage/research/pgpkey.asc
Key fingerprint = F8F2 F5D1 EF74 E08C 02FE  1B90 D7BF 7877 C6A6 F6DA

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