Hackers claim that MSFT DRM can be defeated with MSFT's own tools.
Incredibly, there was no exploit needed. These wily crackers merely had to write a program using well documented 100% aboveboard functions provided by Microsoft. It was not hard, involved no breakthroughs, did not depend on reverse engineering, and did not need a key. All they did was build the right DirectShow graph, and since DirectShow is a tool for third party software developers to build shipping software, ISVs can easily offer an all-in-one solution to strip DRM from content without fear of the DMCA.
(Thanks, Lucas!)