Friday, June 14, 2013

And now unlock your protected Powerpoint Slideshow file


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]

Open the Zip file now.

Not going into details, let us open the folder [ppt]

Drag out the file [presentation.xml] into a folder. We can now view the contents and edit it.
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!!

11 comments:

  1. Thanks :D I have a file protected (ppsx) and your post helped me!

    ReplyDelete
  2. Hi,

    I need to unprotect a pptx file and your method seems promising, but I can't open the file after renaming it with the extension .zip

    Do you know how to solve this issue? You would be of a great help to me if you know.

    ReplyDelete
  3. Hahahahaha.... This is simply terrific!! I've been searching my ass out over the internet for the last 2 days, but to no avail.. and you got it done in like 2 minutes!! Simply awesome buddy!

    ReplyDelete
  4. Wow it really works...
    Thanks man...
    I owe you one...

    ReplyDelete
  5. Thank You, You Are The Best, I Love You So Much, It Was Really Helpful :D

    ReplyDelete
  6. I can't open the file after renaming it with the extension .zip..Please help

    ReplyDelete
  7. You are amazing. It really works. Thanksss

    ReplyDelete
  8. Wow... I searched softwares to unlock ppsx but not satisfied, your technique is very simple. Thanks for sharing.

    ReplyDelete
  9. wow......................yor are amazing. it realy work......thanks a lot......

    ReplyDelete
  10. Hi

    I tried your information to remove the password from a PowerPoint file., and I got pretty far.
    However, I could not delete the lines indicated in your blog.
    Unzipped file is locked.
    What am I missing ?

    I locked the file about 6 months ago and now I cannot remember the password.

    Thanks for the Help

    ReplyDelete