Sometime back, I wrote a post on how to unlock (your own) VBA password protected Excel file with simple tools. More importantly understand how Microsoft organizes its files on the disk. Here is one for a Microsoft Powerpoint Slide show file - recover an editable copy of a protected ppsx file (or similarly a protected pptx file).
Just as we did with the Excel files, lets investigate how Powerpoint stores it file contents on the disk. Create a new Powerpoint Slideshow file MyTest.pptx and enter some dummy content. Choose to file as [ppsx]. Let us now protect it by hitting the [General Options] (from [Tools] in the [Save Dialog]). Set a very complex password. We are safe now. The Slideshow file can be distributed without the contents being stolen.
Going by our earlier experience, we rename our file from [MyTest.ppsx] to [MyTest.zip]
Lets look into this file. Amoung other things we notice that a new node has been added into the xml (as compared to a unprotected file).
hmm...
Seems like the salt and hash of the password we had set. What the heck! Lets delete the node altogether.
Save the file and replace it in the zip file (drag and drop it into the open zip file collection).
Save and close your Zip file. Rename it back to [MyTest.ppsx]. Right click the file and select [New] to open the file in good'ol Powerpoint.
There it goes again. We have an unprotected copy of the Slidehow file that we had created earlier.
Enjoy!!
