Public Vulnerability Reports

Multiple Vendor CUPS CGI Heap Overflow Vulnerability

03.18.08

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/

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.

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.

DETECTION

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

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.

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

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.

DISCLOSURE TIMELINE

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

CREDIT

This vulnerability was reported to iDefense by regenrecht.

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LEGAL NOTICES

Copyright © 2008 Verisign, Inc.

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