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Schneier, UW Team Show Flaw In TrueCrypt Deniability
An anonymous reader writes "Bruce Schneier and colleagues from the University of Washington have figured out a way to break the deniability of TrueCrypt 5.1a's hidden files. What about the spanking-new TrueCrypt 6? Schneier says that 'The new version will definitely close some of the leakages, but it's unlikely that it closed all of them.' Meanwhile, PC World is reporting that the problems Schneier and colleagues found are bigger than just TrueCrypt. Among their discoveries: Word auto-saves the contents of encrypted files to the unencrypted portions of your disk, and this problem should apply to all non-full disk encryption software. Their research paper will appear at Usenix HotSec '08."
HotSex 08? Where do I sign up!
Caesar si viveret, ad remum dareris.
Comment removed based on user account deletion
you run at least full disk encryption. If one needs further plausible deniability, THEN you can run truecrypt. Also, cleaning out temp files should be a regular occurrence, as should running on an encrypted swap file/partition.
So Vista, Word, and Google Desktop make truecrypt less viable? Im Shocked I tell you! Shocked. Please..If you are serious about using truecrypt please tell me that you are savy enough to know how to get around some of these holes. Googledesktop?-aka, I spy on everyone and read your brain desktop? Its like saying my iron has a security hole if someone installs a hardware keylogger on my system. Duh! But just because Schneier is involved, the hacking gods must bow and agree with every word he says. Anyway, now Im rambling, but I use truecrypt only on my secure linux box, which doesnt have these problems. I hide all my stuff that would get me into lots of trouble if!@#@!#%T^GD no carrier
"It's ok, I'm completely secure as long as my iron is off"
True Crypt has a problem eh... Windows should build in a encryption program like on Mac OS X. It would stop a lot problems and it would be Microsoft managed and it would work better because they have all the code for the OS and can provide a better service. In the Mac OS, there are no bugs that I have discovered yet on the built in encryption program. I would hope that True Crypt fixes this bug because it is a great program.
I know there's often mindless maclove on /., but please try to think before posting. So, just to play along, what software do you propose to use on the mac to provide deniable encryption?
SJW n. One who posts facts.
If you're like me (meaning that you pay attention to what you read), you may be wondering what in the world "Word and auto-saves" means. I wondered so much I even followed the link, and saw that the omitted term was Google Desktop, omitted because of very sloppy cut and paste of the article.
I'm an American. I love this country and the freedoms that we used to have.
Some of you may not be aware of the stature of Bruce Schneier in the field of computer security, so here is some background information:
http://geekz.co.uk/schneierfacts/facts/top
Bruce Schneier once decrypted a box of AlphaBits.
Most people use passwords. Some people use passphrases. Bruce Schneier uses an epic passpoem, detailing the life and works of seven mythical Norse heroes.
Bruce Schneier knows Alice and Bob's shared secret.
Vs lbh nfxrq Oehpr Fpuarvre gb qrpelcg guvf, ur'q pehfu lbhe fxhyy jvgu uvf ynhtu.
Bruce Schneier's secure handshake is so strong, you won't be able to exchange keys with anyone else for days.
Bruce Schneier knows the state of schroedinger's cat
Bruce Schneier writes his books and essays by generating random alphanumeric text of an appropriate length and then decrypting it.
When Bruce Schneier observes a quantum particle, it remains in the same state until he has finished observing it.
If we built a Dyson sphere around Bruce Schneier and captured all of his energy for 2 months, without any loss, we could power an ideal computer running at 3.2 degrees K to count up to 2^256. This strongly implies that not only can Bruce Schneier brute-force attack 256-bit keys, but that he is built of something other than matter and occupies something other than space.
Though a superhero, Bruce Schneier disdanes the use of a mask or secret identity as 'security through obscurity'.
${YEAR+1} is going to be the year of Linux on the desktop!
Schneier et al don't break TrueCrypt's deniability, per se. They simply show that Word, Google Desktop, and other automatically-indexing programs may reveal a hidden partition's possible existence.
This is a concern, of course, but can be avoided by careful use of the software invoked when using a TrueCrypt partition (i.e. killing processes except for TrueCrypt, etc).
I believe there's also a portable version of TrueCrypt that can be used that leaves no traces on the OS install once you're finished.
It's better to vote for what you want and not get it than to vote for what you don't want and get it.
- E. Debs
Be careful you don't use slocate if you're on Linux either. (Hint: you probably do without knowing it.)
The point of this paper is that any automatically indexing software could reveal a hidden partition's existence; they were simply giving a few hard examples.
It's better to vote for what you want and not get it than to vote for what you don't want and get it.
- E. Debs
I was wondering about that, I was thinking your security flaw was as simple as someone saying: "Hey, you left your iron on!" then they just rummage through your shit while yer distracted.
"It's ok, im completely secure as long as my iron is off"
Windows should build in a encryption program like on Mac OS X
Uh... they did... 8 years ago.
They've had EFS (encrypting file system) since Windows 2000.
http://en.wikipedia.org/wiki/Encrypting_File_System
They've added BitLocker Drive Encryption with Vista (Ultimate & Enterprise).
http://en.wikipedia.org/wiki/BitLocker_Drive_Encryption
They're not trying to decrypt files here, but just prove that files exist. TrueCrypt lets you put an encrypted volume inside an encrypted volume, such that if you mount the "outer" volume, you can't show evidence that there even exists an "inner" volume. However, if you mount that "inner" volume and use the files in it, Windows will make a Recent Documents shortcut to its location, thus disclosing the fact that there are files there.
I'm a TrueCrypt user, but not a DFS user, since I care more about the encryption than I do about plausible deniability, but I'm interested in trying this out. The test case might be along the lines of:
Since Spotlights also does a full-text search, does it cache any of that full-text data to make the next search faster?
I like music
Any government that would force you to give up such information short of a very serious incident is one that will likely torture the shit out of you until it has proven that either you have a will of steel or don't have an encrypted volume. The "hackers" used in the article are a red herring.
I like Bruce, I think he's got a lot of good insight, but when he spins up a "white paper" that basically says that applications are doing what they're supposed to be doing, and TrueCrypt isn't changing their native behavior, it does everyone in the "Security" community a disservice.
Bruce, if you're trying to make a point - make it. Don't sit there and *publish* nitpicky crap that basically is a bug (or lacking feature) of the software. You'd be far better to say that security applications do not provide adequate deniability, and then cite the sources.
The fact that this sort of stuff passes for "High academia" makes me weep. Let's try to do more than just scratch the surface and point fingers, shall we?
Spotlight's index is stored in the root of the volume it's indexing. Encrypted filesystems are independent volumes, so their indexes are stored in their volume root. The index of the primary filesystem isn't altered.
I'm not sure it leaks zero information -- there have been some bugs with Spotlight indexes and FileVault-encrypted home directories.
Seems that someone found a semi-reliable decryption mechanism that can not only stand up to that, but can reverse an even stronger algorithm known as "volcano".
Didn't mean to dash your dreams, but you know how the security game goes...
Quo usque tandem abutere, Nimbus, patientia nostra?
This has been bugging me and I wonder if anyone out there can answer this: would the write-leveling used by flash drives defeat deniability as well? After all, if the most recently written-to portions of the drive are in a supposedly unused block, isn't that a bit of a giveaway?
Really?
All of Mac OS X encryption operates on user-managed encrypted disk images (volumes) or "encrypted home directories" (FileVault), which is really an OS-managed encrypted disk image.
FileVault home directories are no stronger than your login password. As this password is stored hashed only once (albeit salted, as of 10.4), it had better be immune to brute-force-guessing. They're also only as strong as your system-wide FileVault recovery keychain, as a copy of the key is stored in that, too.
Non-FileVault encrypted images at least use 1000-round PBKDF rather than a single hash and don't, by default, use a recovery keychain. At only 1k rounds, though, it had still better be immune to brute-force guessing.
None of this addresses the fact that using a Mac OS X system with an encrypted directory still leaks information about the contents of that directory onto the unencrypted parts of the drive. In fact, if anything, TrueCrypt is better about not doing this than the Mac, though neither of them hide their tracks all that well. The best approach is to have TrueCrypt running full-disk encryption so that there's nowhere for data to leak to.
Opening an encrypted partition with Windows Explorer is also a risk, because explorer will happily cache the directory structure of everything you browse to. Those paths and filenames show up in the explorer history, even if the drive is offline.
http://www.policystew.com/
you're not a fool per se. everything has deficiencies of one sort or another. but have you looked to see whether there is any configuration guidance for your particular choice?
I know NSA IAD has a security configuration guide for MacOS X. It may include a section on FileVault. If so, it ought to be at least a good place to start from and provide you with good search terms.
http://www.nsa.gov/snac/downloads_macOSX10_4Server.cfm?MenuID=scg10.3.1.1
"If still these truths be held to be
Self evident."
-Edna St. Vincent Millay
Depends, but then you can do turtles all the way down.
So, have an encrypted (obviously visible volume) that has "boring" stuff in it, like your basic groceries accounting and letters to grandma. Have a hidden volume that has embarassing but non-incriminating stuff (porn folders). Have a hidden volume inside THAT that contains embarassing stuff that you'd pretend people shouldn't really want to find out (eg. gay porn). Have a hidden volume inside that that contains your master plan of converting all WoW players into your army of midgets to take over the world...add as many layers as you want.
That's the idea with the deniability, They can never know if there actually is a hidden volume in there. So assuming torture, you are probably so lost yourself that you cannot even remember the scheme yourself anymore...Even if they go with the assumption that since you are using Truecrypt there MUST be a hidden volume - but there's no way to know how many nested hidden volumes there are.
I've been using fire 2.0 for a year already.
I encrypt using a one way algorithm know as "fire" that transforms all my secrets into ashes.
Is that the algorithm invented by the Greek hacker, Prometheus? I heard he got in a bit of trouble over it, he ended up somewhere like Guantanamo, but eventually was rescued.
A more sane conclusion (without that stupid "propritary software" nag at the end) would be:
If you want _deniability_, you have to encrypt _everything_ belonging to the system you want to deny knowledge of.
Have another OS, and page file/partition around. But keep _everything_ that can be accessed by the other OS encrypted.
Otherwise, usage statistics, paged out memory, crash dumps, index files, any of a million different items could give you away.
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
I prefer Axcrypt over Windows Compressed Folders password protection. AxCrypt is free and open-source.
From their FAQ:
Why is AxCrypt better than Windows Compressed Folders password protection?
In the July 2003 issue of PC World magazine, there is a description of how to password protect files using the built-in Windows Compressed Folders of Windows XP and ME. This is a WinZip compatible extension of the Windows Shell (Windows Explorer). The problem is that since it's WinZip-compatible it suffers from the same weakness as does WinZip. WinZip (and thus Compressed Folders) password protected archives use a proprietary and weak algorithm that is known to have the following weaknesses, exploited in numerous 'Password Recovery' products and services:
* If the attacker knows the contents of one of the files in the archive, the password is susceptible to a so-called known plain-text attack. AxCrypt is never susceptible to this kind of attack.
* If the archive contains 5 or more files, password recovery (i.e. cracked protection) is guaranteed. With AxCrypt you can have any number of files encrypted with the same passphrase without affecting the security.
"Keep in mind, though, that you can simply add exceptions to your updatedb.conf file, such that the directories/partitions you list will not be indexed (and hence will not be locatable by slocate)."
yes, put your hidden directories/partitions in /etc/slocate then slocate will not reveal their existence.
It seems to me there is something wrong with this sheme but I cannot put my finger on it. Hum ... but then again I'm not a security specialist.
I'm replying to myself, but I have additional info to add.
[...] it captures live data on the computer, which is why it's important for agents not to shut down the computer first, Fung said. A law enforcement agent connects the USB drive to a computer at the scene of a crime and it takes a snapshot of important information on the computer. It can save information such as what user was logged on and for how long and what files were running at that time, Fung said. It can be used on a computer using any type of encryption software, not just BitLocker.
So it looks like COFEE is a USB device that performs monitoring once Vista has been booted and logged in. Not having your BitLocker USB drive plugged in and not leaving your PC on would seem to defeat an attack by COFEE.
Windows caches all types of stuff about filesystems it touches in the registry. Open regedit some time and search for "OpenSaveMRU" and you'll see that pretty much every file you click to open in Windows is in there.
Not that Linux is any better, at least Gnome systems - check out ".nautilus" in your home folder. Same thing going on there with the directory structure, you name it. The first thing I do on a new Ubuntu box is remove ".recently-used.xbel" and create a directory with the same name, and make ".nautilus" owned by root and not world-writable. /tmp is obviously a problem on Unix-type systems as well, along with the swap partition.
Of course if your whole system is encrypted these are not problems, but then you don't exactly have a deniably-encrypted filesystem.
So, just to play along, what software do you propose to use on the mac to provide deniable encryption?
You could try this program called TrueCrypt. It seems to work okay.
"And there be unix which have made themselves unix for the kingdom of heaven's sake." - Matt. 19:12
You lost me after the first "M$".
You mean it's a one way hash function!
Yes; some of the tools it has perform live evidence acquisition to powered-on systems. It's not safe to assume a powered-on system where the encrypted drive has been disconnected is safe, as keys may remain in memory. But if the PC is off (and especially if free disk blocks, virtual memory and sleep files, etc. are scrubbed), this doesn't do anything.
User Key: [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\ Explorer]
System Key: [HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\ Explorer]
Value Name: NoRecentDocsHistory
Data Type: REG_DWORD (DWORD Value)
Value Data: (0 = disable restriction, 1 = enable restriction)
And you're a captain in the obvious army!
So, just to play along, what software do you propose to use on the mac to provide deniable encryption?
You could try this program called TrueCrypt. It seems to work okay.
yup, ...until some folks showed flaws in TrueCrypt deniability
Now that's an attempt for infinite mod points!
Fortunately, there's an easy way around this problem.
Instead of having just your "sensitive" data in a DFS, just use put an entire OS in there, which you can use with for example VMWare. So, you boot up your machine, type in your encryption password and end up in your safe and clean "nothing to see here" OS, with some decoy applications and VMWare. Then when you want to actually do something with your system, decrypt the DFS, start the VMWare image found there and do your normal work.
All they could prove in this case is that you use VMWare. Just make sure VMWare has no leaks pointing to the image in DFS, but that's trivial compared to cleaning up behind Vista and it's myriad of ways it keeps track of whatever you do (for your benefit usually, but not always).
yup, ...until some folks showed flaws in TrueCrypt deniability
You should just use a Mac. I've never experienced any bugs with its built-in encryption options.
"And there be unix which have made themselves unix for the kingdom of heaven's sake." - Matt. 19:12
Uh, I don't think you get it. We're talking about evil governments here. If you only had "clean" data on your drive, why was it encrypted? That's evidence of guilt in itself (in these people's minds).
And what about deniability, then?
You could try TrueCrypt. I think it works on Macs.
"And there be unix which have made themselves unix for the kingdom of heaven's sake." - Matt. 19:12
Ding, ding, ding!
In many totalitarian regimes the simple existence of crypto or secure delete software is evidence enough to lock you up.
i double encrypt EVERYTHING, even my /. posts, with ROT 13! /Bruce Schneier whistles white noise.
Utilizing the synergization of benchmark e-solutions to pre-workaround action items!
Replying to your sig... Get out of Ohio... Leaving there 10 years ago was the smartest thing I've ever done.
The address for Apple H.Q. is "1 Infinite Loop." So this conversation is kind of appropriate....