In this post, we provide a security analysis of Microsoft Rights Management Services (RMS) and present two working attacks:
- We completely remove the RMS protection of a Word document on which we only have a view-only permission, without having the right to edit it. This shows that in contrast to claims made by Microsoft, Microsoft RMS can only be used to enforce all-or-nothing access.
- We extend this attack to be stealthy in the following sense: We show how to modify the content of an RMS write-protected Word document issued by our victim. The resulting document still claims to be write protected, and that the modified content was generated by the victim