Technical Information

Brief overview of the risk:
The vulnerability could allow remote code execution if a user opens a legitimate file (such as an .xpr or .DESIGN file) that is located in the same network directory as a specially crafted dynamic link library (DLL) file. Then, while opening the legitimate file, Microsoft Expression Design could attempt to load the DLL file and execute any code it contained. For an attack to be successful, a user must visit an untrusted remote file system location or WebDAV share and open a legitimate file (such as an .xpr or .DESIGN file) from this location that is then loaded by a vulnerable application.
Detailed Information on the risk:

A remote code execution vulnerability exists in the way that Microsoft Expression Design handles the loading of DLL files. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

Further information on this exploit is available at : MS12-022