Umm... What exactly prevents you from just typing up your own "contract" and then claiming they sent it to you? Or printing a changed contract out and claiming it was mailed to you? Or taking of any of a million other fraudulent actions? The standard Office protection mechanisms aren't designed (and shouldn't be expected) to be tamper-proof against a determined adversary. For more serious levels of protection, use the new DRM mechanisms in Office 2003. -Eric -----Original Message----- From: Thorsten Delbrouck-Konetzko [mailto:Thorsten.Delbrouck@guardeonic.com] Sent: Wednesday, January 07, 2004 12:57 AM To: bugtraq@securityfocus.com Cc: joop gerritse Subject: Re: Microsoft Word Protection Bypass joop gerritse <jjge@xs4all.nl> wrote on 03.01.2004 12:34:45: > A much simpler trick is to write the document out > in RTF form, and use a text editor. There are several methods to extract the contents of a protected document, but that fails to be the point here. Equipped with a method to unprotect/change/reprotect a document (with the original, unknown password) it becomes (close to) impossible to prove that the document actually *has* been modified. If a senders relies on the protection mechanism (like some corporations which send out offers as "protected" docs do) this might actually have legal consequences. Example: Upon your request a vendor e-mails an offer for product foo to you, price 100,00 EUR (Word format, protected forms). To form a legally binding contract you are asked to print the doc, sign it and send it back. In most legal systems (and among merchants who have been entered as such in a commercial register) this process is suitable to form a legally binding contract between the two parties involved. Now you could easily decide to change the price within the original document to 80,00 EUR, print it, sign it and send it back to the vendor (thus forming a legally binding contract between the vendor and you!). They will of course insist on the 100 EUR version, you will insist on the 80 EUR version. You'll take them to court. An expert will be asked to analyse the original electronic document you received and will most likely find that it's protected by a password which is highly likely to be known by the vendor only and that you could not have changed the document. They lose. You win. :-) regards, /tdk
