Public Vulnerability Reports

Apple Mac OS X mDNSResponder HTTP Request Heap Overflow Vulnerability



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.


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.


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.


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.


iDefense is currently unaware of any workarounds for this issue.


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


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 (, which standardizes names for security problems.


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


This vulnerability was reported to iDefense by Neil Kettle (mu-b) of

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Copyright © 2007 Verisign, Inc.

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