D-Link Router UPNP Stack Overflow
Release Date: July 13, 2006
Date Reported: February 27, 2006
Patch Development Time (In Days): 136
Severity: High (Remote Code Execution)
DI-524 Rev A DI-524 Rev C DI-524 Rev D DI-604 Rev E DI-624 Rev C DI-624 Rev D DI-784 Rev A EBR-2310 Rev A WBR-1310 Rev A WBR-2310 Rev A
A remote stack overflow exists in a range of wired and wireless D-Link routers. This vulnerability allows an attacker to execute privileged code on an affected device. When a specific request is sent to an affected device, a traditional stack overflow is triggered allowing an attacker complete control of the router. With the ability to execute code on the device, it is then possible to apply modified firmware, and ultimately compromise the entire network.
The Universal Plug and Play (uPnP) stack on many D-Link devices is vulnerable to a traditional remote stack overflow. This vulnerability exists on the Local Area Network (LAN) interface of affected D-Link devices. Due to the ease in which one can gain access to the LAN interface of wireless devices, this attack is remote in nature.
The vulnerability exists within the M-SEARCH function. By issuing an M-SEARCH request with an overly long parameter (approximately 800 bytes), a stack overflow is triggered and an attacker can reliably execute code of his/her choosing. This can be accomplished without affecting network connectivity and without any signs of exploitation. In some exploitation cases, the payload may require a soft-reset on the device, interrupting connectivity for a brief moment.
The following request to UDP port 1900 will trigger the stack overflow:
M-SEARCH <800 byte string> HTTP/1.0
Information on exploiting vulnerabilities within embedded systems is scarce. To successfully debug hardware devices you will generally require external hardware for the debugging interface.
I will be giving a presentation at SyScan '06 (http://www.syscan.org) that will demonstrate exactly how to analyze, debug, and exploit embedded devices.
A previous lecture demonstrates the compromise of a network via an exploitable router, these slides are available for download from:
D-Link has released updates for all affected routers and they are available for download from the D-Link website. (http://www.dlink.com)
Credit: Barnaby Jack
B-boys and Fly-girls
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