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Cracking PGP In the Cloud

kdawson posted more than 3 years ago | from the distant-thunder dept.

Encryption 167

pariax writes "So you wanna build your own massively distributed password cracking infrastructure? Electric Alchemy has published a writeup detailing their experiences cracking PGP ZIP archives using brute force computing power provided by Amazon EC2 and a distributed password cracker from Elcomsoft."

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Distrubuted Computing (5, Funny)

Anonymous Coward | more than 3 years ago | (#29961528)

If only they'd thought of using distributed computing for the first post, instead of password cracking!

new UBUNTU 9.10 distro HARBORING MALWARE !! (-1, Troll)

Anonymous Coward | more than 3 years ago | (#29961790)

Cracked big time !!

http://www.theregister.co.uk/2009/11/03/karmic_koala_frustration/?malware [theregister.co.uk]

If you're lucky install fails. If not, you are a fucking zombie !!

And tons of carbon enter the air (-1, Offtopic)

MillionthMonkey (240664) | more than 3 years ago | (#29961546)

At least fold some proteins if you're going to do this. Or look for aliens.

Re:And tons of carbon enter the air (2, Interesting)

HungryHobo (1314109) | more than 3 years ago | (#29961572)

I was under the impression that crypto like PGP was based on stuff which would (in theory) take millions of years to crack even with every machine on earth dedicated to it?

Re:And tons of carbon enter the air (4, Informative)

muckracer (1204794) | more than 3 years ago | (#29961646)

> I was under the impression that crypto like PGP was based on stuff which
> would (in theory) take millions of years to crack even with every machine on
> earth dedicated to it?

That's true if everything's equal. Including your passphrase. If the cipher
for encryption is 128-bit strong, then your password/passphrase needs to match
that. If it doesn't it's the weakest link, easier to attack than the actual
crypto algorithm and will take accordingly less time to crack.

Example: For a password composed only of lower-case a-z english characters,
you'd need 28 characters chosen in a true random fashion (think scrabble tiles
pulled out of a hat) to actually achieve a strength of 128-bit, that matches a
128-bit crypto or hash algorithm.
The strength of TFA 'sweetspot' passwords were somewhere around 60-bits.
Since even RC5 has been broken at 64-bits (distributed.net - though it took
some time), such passwords are OK for low-priority stuff but not, if say, the
NSA is after you ;-)

Re:And tons of carbon enter the air (0)

Anonymous Coward | more than 3 years ago | (#29961716)

I wonder why key strengthening is not used more, even '40-bit' passwords would be pretty tough to crack if each password took 1s to test.

Re:And tons of carbon enter the air (4, Informative)

slim (1652) | more than 3 years ago | (#29961806)

In this case, it sounds like the customer was pretty glad they'd used weak passwords.

The implication is that they'd locked some files up in an encrypted zip, forgotten the password, and wanted the contents back.

If they'd chosen a stronger key, they'd not have got their files back.

TFA:

This analysis may be insightful as you develop your enterprise password policies, or choose your personal passwords.

(A good password policy is: don't forget your passwords!)

DDR (1)

mac1235 (962716) | more than 3 years ago | (#29962754)

Sounds like someone was doing 'Difficult Data Retrieval'

Re:And tons of carbon enter the air (1)

omkhar (167195) | more than 3 years ago | (#29962896)

That is just nonsense.

If the customer had used a proper PKI with key recovery/escrow this could have been avoided. The solution is NOT to make weak passwords so that you can crack them when you lose your passphrase. How on earth is this modded informative?!

Re:And tons of carbon enter the air (3, Funny)

MrMr (219533) | more than 3 years ago | (#29963220)

No problem, I've got a monitor full with post-it notes. So my policy must be excellent.

Re:And tons of carbon enter the air (1)

Forthac4 (836529) | more than 3 years ago | (#29961882)

Sure, if your limiting it to 1 per second, but they can get into the hundreds of millions of passwords per second with GPU setups.

Re:And tons of carbon enter the air (2, Interesting)

buchner.johannes (1139593) | more than 3 years ago | (#29961772)

Schneier had an interesting piece on deriving a limit of the necessary key length from thermodynamics.
http://www.schneier.com/blog/archives/2009/09/the_doghouse_cr.html [schneier.com] ... assuming your password is only bruteforce-able ... otherwise http://xkcd.com/538/ [xkcd.com]

Re:And tons of carbon enter the air (3, Insightful)

psp (7269) | more than 3 years ago | (#29961842)

you'd need 28 characters chosen in a true random fashion (think scrabble tiles
pulled out of a hat) to actually achieve a strength of 128-bit, that matches a
128-bit crypto or hash algorithm.

Scrabble tiles would be an exceptionally bad choice.

Re:And tons of carbon enter the air (2, Funny)

somersault (912633) | more than 3 years ago | (#29962094)

Damnit, my password is all vowels again!

Re:And tons of carbon enter the air (1)

jargon82 (996613) | more than 3 years ago | (#29962124)

and here is why (from wikipedia) English-language editions of Scrabble contain 100 letter tiles, in the following distribution: * 2 blank tiles (scoring 0 points)
* 1 point: E ×12, A ×9, I ×9, O ×8, N ×6, R ×6, T ×6, L ×4, S ×4, U ×4
* 2 points: D ×4, G ×3
* 3 points: B ×2, C ×2, M ×2, P ×2
* 4 points: F ×2, H ×2, V ×2, W ×2, Y ×2
* 5 points: K ×1
* 8 points: J ×1, X ×1
* 10 points: Q ×1, Z ×1

Re:And tons of carbon enter the air (1)

muckracer (1204794) | more than 3 years ago | (#29962288)

> (from wikipedia) English-language editions of Scrabble contain 100 letter
> tiles

I meant using scrabble tiles in principle. So obviously 26 a-z
characters/tiles, not 100 with uneven and therefore non-random distribution. :-)

Wow, no imagination, huh? (1)

zippthorne (748122) | more than 3 years ago | (#29963310)

You take one of each letter, put it them in a bag, jiggle the bag and pull out a single tile. Drop the tile back in the bag and repeat.

You can even get 52 characters out of it: if your thumb covers the letter when you draw it out, capital. If it covers the blank side, lowercase.

Re:And tons of carbon enter the air (0)

Anonymous Coward | more than 3 years ago | (#29961850)

If the encryption software works as advertised, they would need the private key file to exploit this. So as long as you keep your private key file to yourself you should still be safe for a while.

Re:And tons of carbon enter the air (3, Informative)

muckracer (1204794) | more than 3 years ago | (#29962324)

> If the encryption software works as advertised, they would need the private
> key file to exploit this.

You are confusing public key encryption (1 private key & 1 public key) with
conventional/symmetric encryption (gpg -c) where no separate key per se is
required. The encrypted file is all you have.

Re:And tons of carbon enter the air (1)

MikeBabcock (65886) | more than 3 years ago | (#29963358)

An irrelevant note I might add. All PGP/GPG encrypted data is symmetrically encrypted using a randomly generated key. It is only that resulting key that is then encrypted using the public key, for speed reasons.

The security of your data depends heavily on the random number source used for generating these session keys.

Re:And tons of carbon enter the air (1)

muckracer (1204794) | more than 3 years ago | (#29963694)

> An irrelevant note I might add. All PGP/GPG encrypted data is symmetrically
> encrypted using a randomly generated key. It is only that resulting key that
> is then encrypted using the public key, for speed reasons.

Purely from method you're correct. But the distinction made prior between
public key and straight-symmetric is quite relevant to this discussion. If the
files were encrypted with public key encryption and the private key is lost,
you have no other choice but brute-force attacking the cipher with associated
cracking-time. Attacking the password is not even an option anymore, as
opposed to having the files symmetrically encrypted where you can still choose
between attacking the cipher or the passwords.

Re:And tons of carbon enter the air (2, Interesting)

Torrance (1599681) | more than 3 years ago | (#29961892)

I'm also a bit confused. I've never used PGP to make an encrypted zip file, but I use GnuPG to encrypt emails all the time and I, too, was under the impression that it was infeasible in practice to brute force the encryption.

Is the difference that with PGP/GnuPG email encryption, our passwords are merely decrypting our keys which are themselves fully 128 or 256 bits long or whatever? Whereas in this situation with the ZIP file there was no separate key - the password was the key? (I haven't read all of TFA)

Re:And tons of carbon enter the air (5, Informative)

maxwell demon (590494) | more than 3 years ago | (#29962036)

The company surely did have the private PGP key lying around. They just forgot the password.

As an analogy, think of a safe. A good safe is hard to break in if you don't have the key. If you have the key, it's quite easy. Now you fear that someone could break in your house, get the key and open your safe. Therefore you put the key for the big safe into another, smaller safe. If you need to open the big safe, you first open the small safe, take out the key of the big safe and then open that.

Now if you have lost the key for the small safe, and the small safe is less secure than the big safe, you'll certainly not crack the big safe, but just the small safe in order to get the key of the big safe.

Now, the key for the small safe is your password, and the key of the big safe is the PGP key. If someone has access to the small safe (the password-protected PGP key), then the security of whatever is in the big safe is certainly limited by the security of the small safe.

Now with emails, the point is that the big safe (the encrypted email) is out in the public, while the small safe (the password-protected PGP key) is in your home (i.e. on your computer, which hopefully itself has appropriate protection against intruders).

So the security of your PGP encrypted mail is limited by the combination of the security of your computer and the security of your PGP password. If your computer is basically unprotected, and your PGP password is weak, then anyone can read your encrypted mail by simply breaking into your computer, copying the private PGP key, and breaking the password. If your computer is well-secured, the attacker will have a hard time to get your private PGP key, and if you PGP password is strong, the attacker will have a hard time to break it if he manages to get the PGP private key.

Re:And tons of carbon enter the air (3, Interesting)

VoidCrow (836595) | more than 3 years ago | (#29962226)

To pick a trivial example.

Your password is 'password'.

Cracking algorithm attempts to open your encrypted archive using a list of, say, 20,000 english words. 'password' is 5th on the list. After 5 iterations, you notice that your decryption attempt has yielded data that looks like a valid zip archive, or contains english words. Result. You win the internets.

You can refine this.

1. Attempt a password list crack.
2. Attempt a Markov-chain based crack, looking for english-like words generated by your Markov Chain algorithm. Like, say. 'bibble' or 'foglet'. Tr
3. Repeat the above for all letter case combinations, and number/letter replacements - like B1bb7e, or f0Glet.

Et cetera,

The edge you have is that people often choose known words as passwords, or easy-to-remember nonsense words.

This reduces your password search space *hugely*.

For example, say your pgp doodad accepts up to 10 character passwords formed from any combination of letter case or number. 26 lowercase letter, 26 uppercase letters, 10 numbers. Your maximum search space would be the sum of all (26+26+10)^n, where n iterates from 1 to 10, or 853,058,371,866,181,866, or 8.5x10^17. This is the size of the set of all possible mixed case alphanumeric passwords up to a maximum length of 10. You would have to try each of these combinations to fully search this space. This is called 'brute forcing'.

It is a *much* larger number of passwords than the 20,000 in your dictionary list....

So, you use the search space limiting techniques *first*, which will yield a result in 95% of all cases. Then, you try brute force, or give up.

Re:And tons of carbon enter the air (1)

bluefoxlucid (723572) | more than 3 years ago | (#29962824)

You win the internets.

The Internets is full of furries, 4chan, and people having sex with dogs! I don't want this! Take it back!

Re:And tons of carbon enter the air (2, Interesting)

SharpFang (651121) | more than 3 years ago | (#29962086)

I thought the problem was that there was an infinite number of matching passphrases producing invalid results. Like, only a very simple hash or CRC - 1 or 2 bytes checks the validity of the passphrase to protect from common typos, but if you try even semi-hard, you will get a hash collision, the data decrypts, but it decrypts to garbage - a standard GIGO filter with a very weak anti-garbage protection on input.

This way, on top of one correct result you should get an infinite number of incorrect results and unless you have a clue how the correct result should look like and use some heuristics to distinguish it from garbage, you'll be no wiser than before... (and if it was additionally encrypted with anything that makes it look like white noise, there is simply no way to tell it apart from pure garbage.)

Re:And tons of carbon enter the air (3, Informative)

plover (150551) | more than 3 years ago | (#29962432)

That's only a problem if you have no idea what the encrypted data might be. But in most reality-based cases, that's not the problem. You almost always have the clues you need.

In this case, for example, the file is a ZIP archive. That means the archive contains in the clear the original file names including any extensions, such as .jpeg, .bmp, .doc, .pdf, or whatever. All those file types have artifacts you can test for. They all have specific formats. They'll have version numbers, dimensions that must fall within reasonable boundaries, or other attributes that simply won't produce a coherent file unless they're correct.

For example, a JPEG image file is a container and is filled with markers identifying all the different sections. They all must be right or it won't display. So you'd start by looking for the SOI marker as the first byte of the file (0xffd8) or you'd throw it out. After the SOI you'd have to find another valid JPEG marker (two more bytes beginning with 0xFF.) So that's three bytes you'd have to match exactly, and the fourth byte would have to be on the list of valid markers. After you find the next marker, it'll probably be followed by a length (two or four more bytes). If that length is greater than your file size, it's a fail. Sure, if all that passes you'd have to decrypt more data to figure out if you're still in a valid file, but the chances are now only about 1 in 16 million keys tested. You then farm all these "potentials" to a machine or other process dedicated to deeper examination of the candidates.

If I were writing this, I'd have enough smarts in the key tester to look for all possibilities within the first blocksize of the cypher. Anything that looked reasonable at that point would be exported to the "evaluate potentials" system.

Every data file has its structure. You just have to look for it.

Re:And tons of carbon enter the air (1)

perzquixle (213538) | more than 3 years ago | (#29963502)

This is called a known plain text attack. Most modern algorithms are hardened against this. So this technique wouldn't help unless the algorithm had a known weakness to this. But then again, maybe people still encrypt their archives using enigma machines these days. The world is a crazy place.

Re:And tons of carbon enter the air (1)

jargon82 (996613) | more than 3 years ago | (#29962116)

scrabble tiles pulled out of a hat is a bad example :)
They are not evenly distributed, so you'll have a higher occurrence of certain letters (namely the vowels and other common letters like s.)

Re:And tons of carbon enter the air (1)

maxume (22995) | more than 3 years ago | (#29962270)

Really, the set of scrabble tiles in a standard box is a bad example, it wouldn't be real hard to sort out 1 tile of each letter and use those 26 tiles to generate the password (placing the tiles back in the hat and shaking it a bit after each draw).

If we are going to split hairs, we might as well do it all the way.

Re:And tons of carbon enter the air (0)

Anonymous Coward | more than 3 years ago | (#29962392)

scrabble tiles pulled out of a hat is a bad example :)

They are not evenly distributed, so you'll have a higher occurrence of certain letters (namely the vowels and other common letters like s.)

Unless of course you know not to do that and just use the 26 letters comprising the alphabet.

You could even generate a one time pad that way.

Re:And tons of carbon enter the air (2, Insightful)

frozentier (1542099) | more than 3 years ago | (#29962136)

such passwords are OK for low-priority stuff but not, if say, the NSA is after you ;-)

If the NSA is after you, I would think the strength of your passwords is the least of your worries.

Re:And tons of carbon enter the air (3, Insightful)

slim (1652) | more than 3 years ago | (#29961650)

I was under the impression that crypto like PGP was based on stuff which would (in theory) take millions of years to crack even with every machine on earth dedicated to it?

Yes, but the search space is significantly lower if you assume an password that's 1-8 latin alphanumeric characters, as this exercise did.

It's still 122 days on 10 VMs. One tenth of that on 100VMs.

Re:And tons of carbon enter the air (1)

zippthorne (748122) | more than 3 years ago | (#29963668)

If using a cloud, where you pay by CPU-Hour, wouldn't it make sense to use as many VMs as it takes to get it done in.. an hour? (if that many are available)

If I'm understanding right, there's no cost difference, but you get your results right away, instead of waiting half a year

Re:And tons of carbon enter the air (0, Troll)

DNS-and-BIND (461968) | more than 3 years ago | (#29961678)

Was that really your first thought on reading the headline? Sad how tainted people's minds are these days. Reminds me of the preacher who sees Satan's hand in everything or the policeman who is convinced that all teenagers are criminals. When your perspective is that skewed...jeez I don't know what to say.

Assuming I want to use some spare CPU cycles for some purpose or other, where should I apply to make sure it's OK? So far, we have protein folding and alien hunting as acceptable: what are some other uses of spare CPU that are acceptable and unacceptable?

Re:And tons of carbon enter the air (5, Interesting)

plover (150551) | more than 3 years ago | (#29962696)

It wasn't carbon, but the fuel consumed that was my first thought. Back when distributed.net was busy burning energy to win these pointless challenges, I did some rough calculations on the electricity required to solve it.

Turns out that the energy spent breaking RC5-64 used somewhere between 2 and 50 *trains* full of coal.

And that was only the energy directly consumed by the computers involved, and not any of the heating or cooling costs associated with it. And sure, more modern CPUs are more energy efficient, and I extrapolated the figures from a lot of published sources and made a lot of assumptions. But regardless of CO2 or greenhouse gasses or dirty coal or any of that environmental stuff, that's a lot of irreplaceable fossil fuel that's now gone.

I don't think it's sad or tainted to consider the overall impact of what you do. Saying "oh, I want to help search for E.T." is one thing. It may cost you an extra 1440 kWh/day, but you have the money, no big deal. But understanding that SETI@HOME is causing tens of thousands of people around the globe to collectively burn tons of fuel every day might make some of the volunteers rethink their decision. Ignoring that is the kind of perspective that thoughtlessly sucks up our finite resources.

And no, I don't consider alien hunting a valuable use of energy, at least not at this time in our history. Once we have fusion reactors or some other form of "free energy", all that will change.

Go ahead and crack keys, search for Extra Terrestrials, or fold proteins, or whatever you want to do with your box. Leave your lights on 24x7. Run the furnace and the air conditioner together. Just understand that what you do today has an impact, and consider the value of the outcome.

Re:And tons of carbon enter the air (0)

Anonymous Coward | more than 3 years ago | (#29963742)

What's the carbon footprint of your post? Mine has fewer electrons that yours.

Re:And tons of carbon enter the air (3, Funny)

noidentity (188756) | more than 3 years ago | (#29961712)

[And tons of carbon enter the air] At least fold some proteins if you're going to do this. Or look for aliens.

How do you know they weren't cracking a PGP'd zip archive containing secret documents about alien protein folding technology?

Re:And tons of carbon enter the air (1)

EIDETI (1670178) | more than 3 years ago | (#29962186)

Nope. Aliens use bittorrent.

Re:And tons of carbon enter the air (1)

Provocateur (133110) | more than 3 years ago | (#29962336)

Let's see, he already did some 'folding' in the bathroom, while browsing an old old issue of FHM, and
there were no aliens in his morning cereal (just spaceships in purply artificial grape flavor). Came
to work, punched in, and got started. Yup, on time, and right on schedule. boss.

Imagine.... (-1, Redundant)

Anonymous Coward | more than 3 years ago | (#29961554)

Imagine a Beowulf cluster of those.

Pointless (2, Interesting)

Kjella (173770) | more than 3 years ago | (#29961588)

Yes obviously cracking passwords scales linearly, we've known that for a long time. Oh, you could get 100 machines brute forcing instead of one, but what good is that? Either the password is crap and you crack is easily, or it's helluva complex and scaling it up 100x won't do a damn thing. In this case it looks like they just picked some random range and said "Hey, this is unfeasible on a single machine and doable on a cloud, let's do that" but they haven't produced any credible evidence it is in this range. Not unless semi-complex password possibility matches their corporate password policy or whatever.

Re:Pointless (1)

Flibberdy (780254) | more than 3 years ago | (#29961632)

It looks like they were cracking passwords which were 8 or less characters with simple Alphanumerics. In other words, weak passwords. While the cloud aspect makes it vaguely interesting, is it really news?

Re:Pointless (1)

turing_m (1030530) | more than 3 years ago | (#29962672)

It looks like they were cracking passwords which were 8 or less characters with simple Alphanumerics. In other words, weak passwords.

If the guy whose file they are trying to crack uses a password manager, they're screwed. And with it being only trivially more difficult to use maximal passphrase lengths, combinations of uppercase, lowercase and numbers than it is not to, why not future proof yourself?

Of course, since you'll be typing the password for your password manager in all the time, you'd better be computing in a faraday cage if you have any Tempest capable adversaries (they would have to have found your password manager file though). And... at least backup your password manager file regularly. Otherwise the adversary you are fortifying against may well be yourself.

Re:Pointless (1)

kalirion (728907) | more than 3 years ago | (#29963540)

Heh, my password manager is all post-its. Let them get at that through the intertubes!

Re:Pointless (2, Interesting)

Marcika (1003625) | more than 3 years ago | (#29961638)

Yes obviously cracking passwords scales linearly, we've known that for a long time. Oh, you could get 100 machines brute forcing instead of one, but what good is that? Either the password is crap and you crack is easily, or it's helluva complex and scaling it up 100x won't do a damn thing. In this case it looks like they just picked some random range and said "Hey, this is unfeasible on a single machine and doable on a cloud, let's do that" but they haven't produced any credible evidence it is in this range. Not unless semi-complex password possibility matches their corporate password policy or whatever.

It is significant because the lone hacker in his basement or the IT department of your unethical competitor might not have a spare server farm with 200 CPUs lying around. They show just how effortless it has become to do brute-force if you have a couple of minutes to set it up and a few spare bucks for the computing power... (And I bet that very few corporations have a password policy that mandates anything exceeding 8-char alphanumeric - which can be cracked for 45 bucks, as they show...)

Re:Pointless (1)

TheLink (130905) | more than 3 years ago | (#29961764)

It can only be cracked for 45 bucks if the attempt can be parallelized. Which is not always the case.

For example if the password is used for logging into a server, the admins will probably notice 100 amazon machines making brute force attempts, and if it takes seconds per try, that slows things down a lot. More so if the target server "falls over" or crashes in the process ;).

Re:Pointless (1)

wisty (1335733) | more than 3 years ago | (#29961866)

Yes, but what if they recover a hash of the password? It better be well salted ...

In reality, it wouldn't cost 45 bucks. A big botnet would do the heavy lifting, and crack millions of passwords at the same time. Ouch.

Re:Pointless (2, Insightful)

jim.hansson (1181963) | more than 3 years ago | (#29962004)

every hacker worth ther salt [has|knows how to download] precomputed rainbow tables for so easy things, and it does not

Re:Pointless (1)

QuantumRiff (120817) | more than 3 years ago | (#29962878)

I wonder if you can dump your rainbow tables to amazons simpleDB service? If I remember correctly, bandwidth between simpleDB and their virtual servers is free..

Re:Pointless (2, Interesting)

gweihir (88907) | more than 3 years ago | (#29962680)

Yes, but what if they recover a hash of the password? It better be well salted ...

Actually salting does not help against brute-force. It only helps against dictionary attacks.

However other things help, for example instead of running your password/phrase through a crypto-hash once, do it a million times or, say, for 100ms (store the number or iterations). This increases effort proportionally.

Example: SHA-256 does around 100MB/sec on a single modern CPU. That is roughly 3 million hashes/sec. Doing this for 0.1s gives no noticeable interactive delay, but increases the effort 300'000 fold, compared to a single hash iteration. With a 8 char a-z password (4.7 bits/char of entropy, i.e. a total of 37.6 bits), you will need on average 104*10^9 attempts. Each takes 0.1 sec and the EC2 cloud gives something like 8 modern cores for $0.3/h. That would be $7.8 Billion for brute-forcing the password.

See, 8 char a-z passwords are not so bad. The problem here is that the basic PGP design is rather old and these tricks were not used then.

Re:Pointless (2, Informative)

blincoln (592401) | more than 3 years ago | (#29962948)

Actually salting does not help against brute-force. It only helps against dictionary attacks.

It also helps against rainbow table attacks, which I believe the GP was referring to. Salting the hashes makes it much less feasible for someone to develop a rainbow table database, unless they are specifically targeting your system as opposed to every Windows instance on the planet.

Re:Pointless (1)

TheLink (130905) | more than 3 years ago | (#29963442)

Normally if they can get the hash, they're in already... Cheaper ways of getting the actual password once you get to that point.

And the machine will join the botnet too ;).

Re:Pointless (1)

OverlordQ (264228) | more than 3 years ago | (#29961688)

Even TFA story say to cover 50% of the keyspace for a length 12 password you're looking at $1.2M in EC2 fees.

Re:Pointless (1)

Pascal Sartoretti (454385) | more than 3 years ago | (#29961702)

Either the password is crap and you crack is easily, or it's helluva complex and scaling it up 100x won't do a damn thing

Or maybe the password is apparently complex to the average user, but actually not so much. How would you classify "Hello123" or "Hottie69" ?

I am sure that there is plenty of money to be made with people who think that they are safe...

Re:Pointless (1)

tokul (682258) | more than 3 years ago | (#29962080)

PGP cracking is not about breaking passwords. They don't have private PGP keys. Crackers are trying to reconstruct zip file from encrypted data. PGP encrypted zip files are easy targets, because zip has checksums.

Re:Pointless (1)

SharpFang (651121) | more than 3 years ago | (#29962130)

It isn't always true.

For a long time, Windows allowed pretty long samba passwords. Except it didn't make a hash from the whole password supplied, but sequenced it into 8-char pieces which it then hashed and concatenated the hashes.

In most cases, a 9-char password is some 96 times (number of printable characters) harder than an 8-char password, and 10-char password is 96 times harder than 9-char password and so on. In their case, a 16-char password was twice as hard as 8-char password, and a 10-char password was a simple sum of difficulty of an 8-char password and a 2-char one.

Of course if we're talking only about competent implementations, then it's a different matter...

Wanna be careful (1)

aussie_a (778472) | more than 3 years ago | (#29961620)

They will want to be careful or else they just might get arrested. [slashdot.org]

Re:Wanna be careful (0)

Anonymous Coward | more than 3 years ago | (#29961796)

Just like what happened to Randal Schwartz [wikipedia.org] .

In a word (4, Funny)

LizardKing (5245) | more than 3 years ago | (#29961628)

So you wanna build your own massively distributed password cracking infrastructure?

No

They should be discussing bits (1)

skangas (1611225) | more than 3 years ago | (#29961694)

They are only talking about "characters" in a password, which is a bit dubious. The important information is how many bits long the password provides. For a discussion on this see, for example: http://world.std.com/~reinhold/dicewarefaq.html#howlong [std.com] For this reason and others, I'll take their "report" with a grain

Re:They should be discussing bits (2, Insightful)

slim (1652) | more than 3 years ago | (#29961830)

No, they've been approached by a client who's forgotten the password they used. The client's told them they used 1-8 alphanumerics in the password.

In this case, the mapping to a binary key is irrelevant to the size of the brute forcing task.

All communications securely encrypted (2, Interesting)

Frans Faase (648933) | more than 3 years ago | (#29961704)

One of the adversized features of ElcomSoft Distributed Password Recovery is that all network communications between password recovery clients and the server are securely encrypted. How is that possible, I wonder.

Re:All communications securely encrypted (2, Informative)

slim (1652) | more than 3 years ago | (#29961840)

One of the adversized features of ElcomSoft Distributed Password Recovery is that all network communications between password recovery clients and the server are securely encrypted. How is that possible, I wonder.

SSL would do. There's no real magic going on in that network conversation. "Try passwords 'alphabet' through to 'backgammon' and tell me when you're done".

Re:All communications securely encrypted (1)

Frans Faase (648933) | more than 3 years ago | (#29962550)

But SSL is based on the same kind of encryption methods that the system is aimed at breaking. Hence the word 'secure' no longer applies.

Re:All communications securely encrypted (2, Informative)

Abcd1234 (188840) | more than 3 years ago | (#29963296)

Noooo... their system is built to brute-force passwords. That has basically nothing at all to do with cracking an SSL session.

See, SSL uses asymmetric encryption to generate a large-ish session key between two parties, which can then be used in conjunction with a symmetric cipher to protect the session. So, while brute-forcing passwords is really just a matter of throwing hardware at the problem, brute-forcing an SSL session key likely requires more energy than is available in the known universe, which means you're forced to find a weakness in the cipher that you can exploit to reduce the computational complexity of the problem.

Re:All communications securely encrypted (0)

Anonymous Coward | more than 3 years ago | (#29963700)

But SSL is based on the same kind of encryption methods that the system is aimed at breaking.

No, it isn't. How does running through all combinations of n characters relate to factoring prime numbers efficiently?

Bottom Line: Use Long, Unusual Passwords (5, Informative)

Constantin (765902) | more than 3 years ago | (#29961714)

First of all, the article is a very nice summary of the issues involved with setting up a cloud to crack passwords - the nuts and bolts, if you will. I liked that the authors took the time to look into the economics of trying to crack passwords, how much money it would cost vs. how long it would take. Password cracking is one example of massively scalable computing, which is presumably why the NSA allegedly has had to keep upgrading the electrical infrastructure at their headquarters. Elcomsoft certainly made a splash with their PGP-cracking software and managing to harness the power of cheap GPU cards (which are set up for parallel processing) was a bit of genius. That said, even massive horsepower runs into a brick wall once the passphrases become long and the encryption algorithm is good.

On page 2 of the article, the authors nicely summarize the cost of cracking longer and longer passwords. Once passwords start incorporating special characters (per SPEC), the cost shoots sky high even for relatively short passwords (i.e. $10MM+ for a 9 character password, $1BN for a 10-character password, the US national debt for a 12-character password). The article so clearly lays out why the various law enforcement agencies have been focusing on being able to force folk to disclose their encryption keys. The cost of cracking a well-executed encryption scheme combined with a good password is simply too high. So, go ahead and use those special characters, upper and lowercase, etc. to make life interesting for would-be snoops. But realize that unless trends in privacy rights swing the other way, law enforcement will simply compel key disclosure, as they have for years in the UK, for example.

Lastly, the article underscores the value of keychain-type schemes that allow many long passphrases to be stored in a accessible format. Make it easy to have long, complex passphrases and it becomes more likely that people will actually use them.

Re:Bottom Line: Use Long, Unusual Passwords (2, Interesting)

Anonymous Coward | more than 3 years ago | (#29962060)

Passwords are protected in the US by the fifth amendment, for now...

The UK is a different story, though you can always claim to have forgotten your password.

Perhaps an interesting set up would be having 2 computers on separate power supplies running full disk encryption. Each can only boot by requesting a keyfile from the other.

Hence you can shut one down, but when both go down, the two systems become unbootable.

In a police seizure, they will likely disconnect both computers, and unbeknownst to them, completely destroy their chances of recovering the data.

Now no one can compel you to surrender the decryption keys, which can be a good thing or a bad thing. I leave you to think about the de facto punishment courts can issue for contempt.

Re:Bottom Line: Use Long, Unusual Passwords (0)

Anonymous Coward | more than 3 years ago | (#29962444)

The UK is a different story, though you can always claim to have forgotten your password.

No, you cannot do this. It is treated as admitting guilt under the criminal justice act.

Re:Bottom Line: Use Long, Unusual Passwords (0)

Anonymous Coward | more than 3 years ago | (#29962200)

I use Diceware [std.com] for all my obscenely long password needs

Re:Bottom Line: Use Long, Unusual Passwords (1)

dissy (172727) | more than 3 years ago | (#29962620)

Password cracking is one example of massively scalable computing, which is presumably why the NSA allegedly has had to keep upgrading the electrical infrastructure at their headquarters.

Naa, the current state of the art is in Rainbow tables [wikipedia.org] , which lets you do the brute force method once ahead of time, then reuse those generated tables to crack literally any password covered by that table in seconds.

If your system only allows ASCII characters (255 different values per character) and lets say 256 characters max in your password, you can setup and generate a rainbow table that matches using the same hashing method.

At that point, throwing any hash (any hash that will allow one to actually login that is) into the table, and plaintext pops out in seconds. Rinse and repeat for the entire password file.

Generating the rainbow tables does take a lot of time, and is a great example where distributed processing greatly speeds things up.
The NSA already has access to such computing resources however and can generate said tables in a much quicker time than any of us most likely can. The generation process only needs done once per hashing method as well.

Brute forcing hashes in real time on an as-needed basis is so 90s ;}

Re:Bottom Line: Use Long, Unusual Passwords (0)

Anonymous Coward | more than 3 years ago | (#29962702)

You should look up "salting hashes" and see why Rainbow tables are useless.

Re:Bottom Line: Use Long, Unusual Passwords (1)

dissy (172727) | more than 3 years ago | (#29963382)

You should look up "salting hashes" and see why Rainbow tables are useless.

So for the bulk of systems that do not salt hashes, why exactly are rainbow tables useless?

Re:Bottom Line: Use Long, Unusual Passwords (1)

R2.0 (532027) | more than 3 years ago | (#29963132)

"On page 2 of the article, the authors nicely summarize the cost of cracking longer and longer passwords. Once passwords start incorporating special characters (per SPEC), the cost shoots sky high even for relatively short passwords (i.e. $10MM+ for a 9 character password, $1BN for a 10-character password, the US national debt for a 12-character password)."

Ok, here's a question. Does the benefit of special characters in passwords derive from their actual use or in the expansion of the possible character set? If the possible character set includes the special characters, must they then be used in order to gain the advantage?

I ask because I always thought that "formula's" for strong passwords actually weakened them. First, because of human factors - make it too complex and everyone defaults to "Password-1", "Password-2", etc. But second, if the rules narrow down the possible contents of a password, doesn't that make it easier to crack? For instance, my current favorite is "Minimum X, maximum Y characters, must have an upper case, lower case, number, and symbol" So now the potential solution includes those rules as well - for instance, in a password X characters long, the maximum number of lower case letters is X-3. Doesn't that make the solution easier than if the character choice is wide open? I'm not trying to be a smartass, just increasing my knowledge.

Re:Bottom Line: Use Long, Unusual Passwords (1)

houghi (78078) | more than 3 years ago | (#29963148)

The idea is good if you only have 1 login and password. However I and I asume many others have a multitude of logins and passwords. I access systems from different systems with different Operating Systems and different software.

Many logins and some passwords are not ones I can select myself. And then I am not even talking about the need to change passwords every month. (Some think that 30 days is a good idea.) So every first of the month I am changing as much passwords as I can, so I don't need to remember them all.

Obviously I forget some along the way.

Complex passwords? The more complex they must be, the more post-it notes I see on screens where I work.

I just checked and for my work I have 20 differnt logins and passwords that I did not made myself and where I have no influence on the login or the password. This due to many of them being third parties or shared ones with others. And now three devices that I need to type something in.

Sure it is very bad. It is however the situation I am in and I can imagine that I am not alone there.

Interesting but misleading (0)

Anonymous Coward | more than 3 years ago | (#29961776)

People who would try to hack your password probably will not use Amazon's EC2, but something far more trivial, such as a botnet. Botnets are free, all you need is some time.

This is why I wouldn't think that 11-12 character bound has any meaning in practice. A more meaningful boundary is the one which can not possibly be cracked in reasonable time with a big computer network, regardless of the cost of operating it.

I use a composite password approach that gives a best balance between security and ease of use: use a good random generator for say 16 characters. Print it. This is not your password yet. You will come up with a few easy to remember, but hard to guess transforms, such as inserting several characters in a place only you know, using the printed sequence in a different order than linear left-to-right, and replacing all instances of printed "a" with "3" for example.

This ensures brute-forcing over the network will not be possible, as your password is truly random, and long. Finding the list would not lead to instant hack either as there's still reasonable information withheld from what's printed. You can also frequently change the "seed", the random characters you print, and apply the same rules you remember from before, to arrive at a completely new password, without having to remember anything new.

Can't you snoop on this ? (1)

absolovon (1670112) | more than 3 years ago | (#29961788)

If you are cracking through the cloud, then you are also vulnerable, and someone can use your efforts to get into the system before you...

Re:Can't you snoop on this ? (2, Informative)

slim (1652) | more than 3 years ago | (#29961854)

Only if your communications with the cloud are in the clear. Why would they be?

In other news (-1, Offtopic)

Anonymous Coward | more than 3 years ago | (#29961838)

Elcomsoft has been charged with conspiracy, aiding and abetting computer intrusion and wire fraud.

http://www.wired.com/threatlevel/2009/11/derengel/ [wired.com]

Windows, yuck (1)

hey (83763) | more than 3 years ago | (#29962026)

What chore that they need to use Windows. For a brute force password guesser, most Slashdotters could write it in 10 lines of perl.

Re:Windows, yuck (3, Funny)

rvw (755107) | more than 3 years ago | (#29962346)

What chore that they need to use Windows. For a brute force password guesser, most Slashdotters could write it in 10 lines of perl.

I think ten lines of Perl would be the ideal password somehow.

Hmm (1)

ShooterNeo (555040) | more than 3 years ago | (#29962034)

I have an idea : how about a self destructing key? There would be a physical USB key that would have your passphrases on it. The passphrases would be quite lengthy strings of randomly generated characters, effectively un-forcable unless there's a massive weakness in the encryption algorithm.

The key would have a small CPU and lithium ion battery. All the components would be potted in epoxy, and you would be able to put an outer shell around the key resembling a common brand of USB stick.

In order to use the key, you'd have to enter a small password to unlock it. If the key has not been used in roughly 2 weeks of real time, it erases the passphrase from itself.

So if you get arrested or compeled to give up your password, you just have to keep silent for a couple weeks. Then, it's gone!

Re:Hmm (4, Interesting)

jonwil (467024) | more than 3 years ago | (#29962208)

The best solution (if you are dealing with a desktop system) is to have the pass-phrase and keys but also have a small GPS module. If the usb key is not close to where it should be (with a fairly big margin for the fact that cheap GPS modules arent exactly accurate) it would erase the pass-phrase

If they try to force you to hand over your password (e.g. UK RIP act), you just hand it over (to the guys who seized your computer and are now trying to use it somewhere else other than the required GPS location) and boom, the data is gone forever.

If you need to move house, just log in from the old house and reset the GPS then when you get to the new house, log in and put in the new coordinates.

Re:Hmm (1)

ickleberry (864871) | more than 3 years ago | (#29962262)

falsifying the coordinates wouldn't be hard. serial port + null modem => fake GPS data and the password still works.

Re:Hmm (2, Interesting)

jonwil (467024) | more than 3 years ago | (#29962326)

The best answer of all is "physical seganography" i.e. 802.11 NAS built into something that the cops are unlikely to seize (yet which has a legitimate need to be plugged in and doing what it does)

Less geeky solution (0, Redundant)

dazedNconfuzed (154242) | more than 3 years ago | (#29962626)

A much less geeky/costly solution than using a GPS-integrated self-destruct mechanism is: ...have two passwords. One decrypts the data, the other erases it.

Actually, some ATMs have a similar ability: your PIN lets you access your bank account, while entering your PIN backwards does the same thing but calls the cops at the same time. If you're mugged at the ATM and forced to reveal your PIN, you give/use it backwards to notify police while the perp is busy emptying your savings.

Re:Less geeky solution (2, Informative)

Anonymous Coward | more than 3 years ago | (#29962774)

Can we get a "-1 Wrong" moderation option?

Funny sig considering your post. Look, first thing; the authorities aren't stupid. The first thing they do is mirror your data, then test the passphrase you give them on the mirrored data. When your phassphrase deletes the data, they still have a copy backed up, and now you've bought yourself a prison sentence, or worse.

As to entering your ATM passphrase backward, that doesn't work anywhere. Some guy tried to make it a standard, but the authorities, noticing immediately all the problems with it, choose not to implement it anywhere. If you think you're right, and want to prove me wrong, go to Snopes and look it up.

Re:Less geeky solution (0)

Anonymous Coward | more than 3 years ago | (#29963218)

According to snopes [snopes.com] , the reverse pin alert was an idea, patented in the 90s, that was never implemented.

Re:Less geeky solution (1)

bluesatin (1350681) | more than 3 years ago | (#29963354)

My PIN is 2662, you insensitive clod!

Re:Less geeky solution (1)

Blapto (839626) | more than 3 years ago | (#29963444)

Are you sure about this entering your PIN backwards trick? The only real reference I can find is a 6 year old article: http://www.msnbc.msn.com/id/4086277/ [msn.com] and they imply that it's possible but nobody has implemented it. Any other searching just throws up snopes like sites debunking it as a hoax.

Re:Hmm (1)

Sir_Lewk (967686) | more than 3 years ago | (#29962406)

It seems like every time someone comes up with a new "unbreakable security scheme" on slashdot their pitch always starts with something to the effect of "so we start with this USB key...". Such measures are more about physical security, than crypto security. All you are really saying is "good long keys are more secure", which everyone already knows.

I might as well say, "Well if I light my computer on fire (and use longer keys) then ninjas won't be able to steal it".

Use a bot net rather (0)

Anonymous Coward | more than 3 years ago | (#29962142)

Much more horse power and it don't cost you anything. Thank god for windoze lusers.

uggboots (-1, Offtopic)

Anonymous Coward | more than 3 years ago | (#29962278)

Eric, thanks for such a great post- I really enjoyed it, actually reading this

I have been really interested in this topic .
girl ugg [uggbootshare.co.uk]

Not the way of doing it (4, Insightful)

julesh (229690) | more than 3 years ago | (#29962280)

I looked at EC2 for raw processing power earlier this year (my company needs to train a lot of neural nets) and it just isn't worth it, unless you only need the power short term. A high-performance EC2 node gives you 8 cores running at (very roughly) the equivalent of a 2GHz P4, and costs $0.68/hr == about $460 per month, which is only a little less than what an equivalent box (probably a 2.83GHz Core 2 Quad or similar) would cost you. Put power to run that box down at about $0.05 per hour and you can build your own local cluster of equivalent performance for around the same amount of money as you'll save in your first month and a half of operation.

Re:Not the way of doing it (3, Interesting)

gweihir (88907) | more than 3 years ago | (#29962768)

I looked at EC2 for raw processing power earlier this year (my company needs to train a lot of neural nets) and it just isn't worth it, unless you only need the power short term. A high-performance EC2 node gives you 8 cores running at (very roughly) the equivalent of a 2GHz P4, and costs $0.68/hr == about $460 per month, which is only a little less than what an equivalent box (probably a 2.83GHz Core 2 Quad or similar) would cost you. Put power to run that box down at about $0.05 per hour and you can build your own local cluster of equivalent performance for around the same amount of money as you'll save in your first month and a half of operation.

Indeed. EC2 is rather expensive for most applications. It really only pays off if you may need a lot of power on short notice (but usually need none). The article describes one of the very few general applications. There is also the problem that even EC2 only scales so far. You would probably not get the cores to do a 12 char password in parallel. In addition, EC2 has problems like confidentiality and data transfer also costs money. And you have no control over how reliable and available the resources are.

Having done a (small) bit of high-performance computing myself, I believe the most cost effective way is to get some bright people that do understand current computer hardware and your problem, and then have them get the hardware they think does the job best, preferably of the white box variant. I went so far to get components, because having a student assemble them got me something like 20% more cores for the same money and exactly the hardware I wanted. Never had serious issues in several years with the resulting infrastructure.

Re:Not the way of doing it (3, Insightful)

Slashdot Parent (995749) | more than 3 years ago | (#29963676)

Don't forget other cosets: cooling, system administration, datacenter space, backups, racks, switches, KVMs, UPSs, network administration, maintenance, etc.

No question EC2 is expensive if you plan on fully-utilizing that hardware. But that's why it's called the Elastic Compute Cloud, not the Static Compute Cloud. If your computational needs are static, EC2 is most definitely the wrong tool for the job.

But did it work (2, Interesting)

Anonymous Coward | more than 3 years ago | (#29962766)

FTA, they mention that Amazon didn't allow them to create more than 9 instances, so they couldn't crack the passwords in less than 122 days. (a request to get suitable amounts of computing power was made, but takes time, is not enabled by default, and wasn't available at the time of writing?)

Dear Sir,Thank you for submitting your request to increase your Amazon EC2 limit. It is our intention to meet your needs. We will review your case and contact you within 3 - 5 business days.

That's no moon... (0)

Anonymous Coward | more than 3 years ago | (#29963130)

what if we covered the moon with graphics cards?
i bet we could break any password then, huh guys

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