Microsoft Windows fails to properly handle protocols specified in a URI, which could allow a remote, unauthenticated attacker to execute arbitrary commands on a vulnerable system.
A Uniform Resource Identifier (URI) is a string of characters that can be used to identify a location, resource, or protocol. Microsoft Windows will parse a URI to determine the appropriate application that is registered to handle the protocol. More information about how Windows accomplishes this is available in Microsoft Knowledge Base article 224816. Several types of Windows applications, such as web browsers and email clients, may rely on Microsoft Windows to determine the proper application to handle a specified URI.
Internet Explorer 7 has changed how Microsoft Windows parses URIs. This has introduced a flaw that can cause Windows to incorrectly determine the appropriate handler for the protocol specified in a URI. This flaw appears to rely on having a "%" character in the URI.
Microsoft Windows may incorrectly determine the appropriate application to handle a protocol. For example, a "safe" protocol such as mailto: may be incorrectly handled with an "unsafe" application, such as the Windows command interpreter. This can allow unexpected execution of arbitrary commands.
Apply an update
This vulnerability was publicly disclosed by Billy Rios.
This document was written by Will Dormann.
|Date First Published:||2007-07-27|
|Date Last Updated:||2007-11-13 21:21 UTC|