Removing Adobe Policy Server/ livecycle DRM from PDF files

This is a tutorial for removing DRM for PDF files that use Adobe Policy Server to set DRM security. 

Identifying files that use this kind of DRM is easy since every time you open them, Adobe reader (or acrobat) will ask for permission to connect to the publisher's server that is managing DRM for the file.



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What you need -- 
- drm PDF file 
- fiddler 2
- Adobe Acrobat (not reader)
- notepad++ (not necessary but will help)


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1- Install fiddler, run it
2- Go to tools menu> fiddler options > HTTPS tab 
3- Check the "decrypt HTTPS traffic" checkbox 
//this allows fiddler to 'fiddle' with ssl traffic.

4- You will get a dialog box saying "SCARY TEXT AHEAD" .. click yes
5- You will get another dialog box which will ask you if you want to install a certificate .. click yes, click ok on fiddlers options window

//In the above two steps you have just told windows to accept the fiddler's own SSL certificate as genuine

6- Goto rules menu> customize rules .. this will open up a .js file in notepad 
OR, go directly to C:\Users\xxx\Documents\Fiddler2\Scripts and open 'CustomRules.js' in notepad++

7- Search for 

static function OnBeforeResponse(oSession: Session) {

and insert the following after the bracket

if (oSession.HostnameIs ("drm.dawsonera.com" && oSession.oResponse.headers.ExistsAndContains ("Content-Type", "text/xml;charset=utf-8") {oSession.utilDecodeResponse (); oSession.utilReplaceInResponse ("com.adobe.aps.pdf.accessible","com.adobe.aps.policySwitch"}

http://pastebin.com/ssJnfuaX

before-- 


after--


8- Save the file and restart fiddler

// from now on when fiddler is running every time the APS server replies, fiddler will look for the string "com.adobe.aps.pdf.accessible" and replace it with "com.adobe.aps.policySwitch"

9- Open the file PDF file in question in acrobat and clcik yes as normal on the window that asks to the connect to the APS server.

10- In Acrobat go to Advanced menu > Security > show security properties
11- In the 'security method' dropdown select 'no security'



12- Do File>save or Ctrl+S, Your DRM free file is ready!

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In my case the file also had watermarks of the library's name which automatically got removed after removing the DRM.

In step 7 you can edit the "drm.dawonera.com" bit to match the name of the server you see while opening the file in acrobat

In step 8 the location of security options may vary depending on the version of acrobat you are using. I am using version 8. 


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The method is different (and much easier) from the older method which used python scripts or required you to setup an apache+php server to figure out the 'principle key' for the retailer.
Its called a MITM (man in the middle) attack since we are modifying the response from the publisher's DRM server to fool Acrobat into giving us full control over the PDF. We of course use this to remove the need for bothering the server at all for using our PDF file. 
All credit for this method goes to fagmxli and Qupfer, on boerse.bz who suggested and gave instructions for using fiddler.