Exploiting DLL Hijacking Flaws

This post describes the process for identifying and exploiting applications vulnerable to the DLL hijack vulnerability disclosed last week. For background information on this vulnerability, as well as remediation information, please see my post on the Rapid7 Blog.Update: The audit kit has been rewritten, please ignore the instructions in this post and read this post for information on the new kit.This vulnerability is triggered when a vulnerable file type is opened from within a directory controlled by the attacker. This directory can be a USB drive, an extracted archive, or a remote network share. In most cases, the user will have to browse to the directory and then open the target file type for this exploit to work. The file opened by the user can be completely harmless, the flaw is that the application launched to handle the file type will inadvertently load a DLL from the working directory.In practice, this flaw can be exploited by sending the target user a link to a network share containing a file they perceive as safe. iTunes, which was affected by this flaw until last week, is associated with a number of media file types, and each of these would result in a specific DLL being loaded from the same directory as the opened file. The user would be presented (continue reading...)