iDefense Security Advisory 03.18.08
http://labs.idefense.com/intelligence/vulnerabilities/
Mar 18, 2008

I. BACKGROUND

The Common UNIX Printing System, more commonly referred to as CUPS,
provides a standard printer interface for various Unix based operating
systems. For more information, visit the vendor's website at the
following URL.

http://www.cups.org/

II. DESCRIPTION

Remote exploitation of a heap based buffer overflow vulnerability in
CUPS, as included in various vendors' operating system distributions,
could allow an attacker to execute arbitrary code with the privileges
of the affected service.

CUPS listens on TCP port 631 for requests. This interface provides
access to several CGI applications used to administer CUPS and provide
information about print jobs. By passing a specially crafted request,
an attacker can trigger a heap based buffer overflow.

III. ANALYSIS

Exploitation of this vulnerability results in the execution of arbitrary
code with the privileges of the affected service. Depending on the
underlying operating system and distribution, CUPS may run as the lp,
daemon, or a different user.

In order to exploit this vulnerability remotely, the targeted host must
be sharing a printer(s) on the network. If a printer is not being
shared, where CUPS only listens on the local interface, this
vulnerability could only be used to elevate privileges locally.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability in CUPS
version 1.3.5. Previous versions may also be affected.

V. WORKAROUND

Disabling printer sharing will prevent this vulnerability from being
exploited remotely. However, local users will still be able to obtain
the privileges of the CUPS service user.

VI. VENDOR RESPONSE

Apple Inc. has addressed this vulnerability within Security Update
2008-002. For more information, visit the following URL.

http://docs.info.apple.com/article.html?artnum=307562

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2008-0047 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for
security problems.

VIII. DISCLOSURE TIMELINE

02/26/2008  Initial vendor notification
02/26/2008  Initial vendor response
03/18/2008  Coordinated public disclosure

IX. CREDIT

This vulnerability was reported to iDefense by regenrecht.

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X. LEGAL NOTICES

Copyright © 2008 iDefense, Inc.

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Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
 There are no warranties with regard to this information. Neither the
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reliance on, this information.