Microsoft Enhanced Mitigation Experience Toolkit (EMET) before 4.0 uses predictable addresses for hooked functions, which makes it easier for context-dependent attackers to defeat the ASLR protection mechanism via a return-oriented programming (ROP) attack.
http://www.securitytracker.com/id/1029411
http://en.nsfocus.com/advisories/1301.html
http://blogs.technet.com/b/srd/archive/2013/06/17/emet-4-0-now-available-for-download.aspx