Public Vulnerability Reports

Apple Mac OS X mDNSResponder HTTP Request Heap Overflow Vulnerability

08.07.07

BACKGROUND

mDNSResponder is part of the Bonjour suite of applications. Bonjour is used to provide automatic and transparent configuration of network devices. It is similar to UPnP, in that the goal of both is to allow users to simply plug devices into a network without worrying about configuration details. mDNSResponder runs by default on both Server and Workstation. More information can be found on the vendor's website.

http://developer.apple.com/opensource/internet/bonjour.html

DESCRIPTION

Remote exploitation of a heap overflow vulnerability in Apple Inc.'s mDNSResponder application may allow attackers to execute arbitrary code with root privileges.

The vulnerability exists within the Legacy NAT Traversal code. Unlike the core of the mDNSResponder service, this area of code does not rely on Multicast UDP. It listens on a dynamically allocated Unicast UDP port.

The vulnerability occurs when parsing a malformed HTTP request. This results in an exploitable heap overflow.

ANALYSIS

Exploitation of this vulnerability allows an attacker to execute arbitrary code with root privileges on a vulnerable host. No authentication is needed to exploit this vulnerability.

Failed attempts will result in the service crashing. Shortly after crashing, it will be restarted.

DETECTION

iDefense has confirmed the existence of this vulnerability in Mac OS X version 10.4.10, Server and Workstation, with mDNSResponder version 108.5. Previous versions may also be affected.

WORKAROUND

iDefense is currently unaware of any workarounds for this issue.

VENDOR RESPONSE

Apple addressed this vulnerability within their Mac OS X 2007-007 security update. More information is available at the following URL.

http://docs.info.apple.com/article.html?artnum=306172

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2007-3744 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

07/26/2007 Initial vendor notification
07/26/2007 Initial vendor response
08/07/2007 Coordinated public disclosure

CREDIT

This vulnerability was reported to iDefense by Neil Kettle (mu-b) of www.digit-labs.org.

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LEGAL NOTICES

Copyright © 2007 Verisign, 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 author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information.