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Microsoft Word Forms Passwords Hacked
An anonymous reader notes: "SecurityFocus has published a hack that can be used to unlock Microsoft Word documents that have been password protected. The 'secure' file can easily be edited and the original password re-inserted, removing any trace of the modification. A ZDNet UK article says Dell uses password protected Word files to send quotes, which could make for a messy legal battle." This feature, known as 'Password to Modify', is not the password protection on the document itself, just the protection that restricts unauthorized editing of the file. This hack allows someone to download such a file, edit it, and restore the password...effectively allowing changes to the file to go potentially unnoticed.
There have been utilities to obtain Word passwords for quite a while. I've tested mine on Office 2000 and XP protected documents and had great success.
What's odd: The password returned by my tool of choice is not the same as the one actually stored - but when I enter this new password OR the original password into Word, the document is successfully unprotected. Some sort of odd math that makes more than one password work?
Example - I protected both a Word 2000 and Word 2002 document with the password "test" then ran them through my cracker. The cracker returned the password "QFQDOBCTGLHGEE" virtually instantly for both documents. Oddly enough, this new unusual password successfully unlocked both Word documents using Tools > Unprotect Document. Subsequent testing reveals that the original password will also unprotect the document.
So, if such passwords can easily be bypassed anyway - what does this really change?
I should note that I'm using a Passware product called Office Key.
This crack just takes what has been commercially available for quite some time and moves it into the public arena.
Josh
How many roads must a man walk down? 42.
According to Microsoft, the password protection feature on Word is not intended to be secure, but should be regarded as a means to protect documents against accidental modification. I use Word and don't ever recall being advised of this, but then I suppose the EULA does warn users never to actually rely on the software for anything important.
I never expected the protection in Word to be anything special, but sometimes (as shown here by Dell) it's better to have no security than false security because that way you take greater care.
But for those of you who never RTA, here is what was the highlight for me:
Aide-toi, le Ciel t'aidera - Jeanne D'Arc.
I swear, you guys gave me a quote of $6.35 for a new Latitude.
If I recall, openoffice/staroffice can open "encrypted" Word and Excel documents without the requirement of a password. I know this used to work for older versions...
-- Minds are like parachutes... they work best when open.
Come to think of it, I can't think of a real position where this could be a problem. What would someone do, host protected
Etiquette is etiquette. He kills his mother but he can't wear grey trousers.
Passwords can use a one way function.
Take the source string, do a bunch of 'stuff' to it, stuff that isn't easy to undo.
You can throw out some data too.
You end up with a new string, but since you threw out some information, you end up unable to reverse it.
Even if you know the end result, and the formula, you can't guess the password. You'd have to brute force it.
With slow computers, this was a very good obstacle. Now we use fancier algorithms, and it is still okay.
I'm not a math guy, go read crypto books if you want the 'real' explanation
Without some type of private/public digital signature system, you're going to see problems like this. Don't trust passwords on supposed read only documents as a general rule.
The sooner business people understand these things, the sooner that we'll all see the benefits of a standardized, omnipresent public key infrastructure. Make sure to educate the nontechnical people in your office so that they demand better security for their data.
Why are you letting these clowns ruin our country?
The fact that it can't determine your actual password is a good thing. Not for the security of that particular document, obviously, but for the security of other things you may have used the same password for.
I work with Dell for our workstation and laptop purchases and not once in the last 3 years have they sent me a quote in a Word document.
They have a system that links the quote with your customer ID and gets generated as an HTML file which gets emailed to you. All automagically.
To whom ever that thought they could change a word document quote and expect to get that price, I got some beach front property to sell you in Kansas. Silly fool.
that I noticed my customer was a 12 foot tall monster from the crustacious period! He looked me right in the eye and said, 'My quote for the dell says about Tree-Fitty!' and I said GOD DAMN YOU LOCHNESS MONSTER!
2003-11-27, 10:30 UTC Microsoft notified to: secure microsoft com
2003-11-27 confirmed receipt from: secure microsoft com
2003-12-03 Note from Microsoft, Form protection "is not intended as a full-proof protection for tampering or spoofing, this is merely a functionality to prevent accidental changes of a document", request additional time to update Microsoft Knowledge Base article.
Targetting beginning of January 2004 for release of this advisory.
from: "Magnus"
2003-12-08 Microsoft has already released the KB article (or added a warning to an existing article). Read the KB article at http://support.microsoft.com/?id=822924
from: "Magnus"
bad sig...no donut.
Was this ever really meant to be really truly secure? "security" features like that have always been lame at best and equivalent to luggage locks. These passwords have always been susceptible to brute force attacks. Anyone really serious about keeping documents safe puts them into a source control program. There are many ways to pick at MS's security, this is not one of them. But if you are trusting these measures for really secure documents, I highly suggest you get your valuables out of the pink plastic safe you won at the county fair last year.
Probably someone who truly believes their software is so ubiquitous that there would be no such thing as "hostile software."
If the program claims that you can lock a document against modification, then shouldn't it provide verification of that? Or does it believe in its infallability.
I know MS word includes signatures, why wouldn't a signature be an automatic feature on a locked document???
shame.
I saw a good point the other day that US export laws on cryptography were fairly stupid when you consider that other countries have the skills/intelligence to develop strong cryptography outside the US in the first place. For example, RSA was originally developed in the UK.
> OK, I'm not saying that Microsoft's totally without guilt here but just how far do people think they need to go with regards to securing passworded files? 48-bit encryption? 128-bit? 160-bit with triple DES? At what stage does the encryption become overkill?
So long as we ride the Moore Curve, overkill degrades to underkill at a rate of about one bit per 18 months. So if you want your document to be secure in perpetuity, you'd better use a lot of bits.
Sheesh, evil *and* a jerk. -- Jade
Microsoft pointed to this Knowledge Base article. Choice quote: "Not all features that are found on the Security tab are designed to help make your documents and files more secure."
First of all, if you read the article, you will understand that Microsoft has not been advertising these "Word document passwords" as true security mechanisms. Microsoft has been pushing its new DRM Features in Office 2003 as the Microsoft-approved method to secure Office documents.
In fact, I doubt Microsoft really put much effort into making these document-modification passwords all that secure. They have been around for quite some time, and I doubt they have changed much or improved much over the years. I don't know anyone who was relying on these document passwords for their security, and Microsoft did not advertise this as a great feature of Word. In fact, the bug itself is limited in scope to protecting Word FORMS from being modified.
In any case, the new DRM features in Office 2003 are much more sophisticated and will no doubt be much more difficult to crack. THESE are the security features that Microsoft is pushing today, and if you really want to lambast Microsoft Security, then you must point out a way to subvert these newer technologies that Microsoft is actually pushing.
It would be very big news indeed if someone could succeed in copying an Outlook 2003 email marked with a "Do Not Forward" permissions flag. Indeed, if someone could even READ such an email on an unauthorized email client, Microsoft's newest security policies would be questionable. Until then, I'm not convinced this is anything more than FUD trying to convince people that Office is inherently insecure.
This came up at work. What happens if: You send out a contract as a Word doc email attachment. Customer changes the language of the contract, signs it, prints it, then mails it back. We could easily sign that without noticing the difference.
We decided to send out digitally signed PDFs instead.
So long as we ride the Moore Curve, overkill degrades to underkill at a rate of about one bit per 18 months. So if you want your document to be secure in perpetuity, you'd better use a lot of bits.
Take something like 256 bits, which is quite commonly available, and you'll see that brute forcing it requires you to turn each atom on earth into a computer, and compute with each of the atoms of the earth (2^171 atoms) at 1 THz (2^40) for 1 million years (2^45) in order to brute force *one* key.
Now, if that is too unsecure for you, I recommend you seek professional help. Fast.
Kjella
Live today, because you never know what tomorrow brings