Date: Mon, 31 Mar 2003 18:07:24 +0800
From: NSFCOSU Security Team <[email protected]>
To: [email protected]Subject: NSFOCUS SA2003-02: Solaris lpq Stack Buffer Overflow Vulnerability
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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.
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==========
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NSFOCUS Security Team <[email protected]>
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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