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Amazon EC2 Enables Cheap Brute-Force Attacks
snydeq writes "German white-hat hacker Thomas Roth claims he can crack WPA-PSK-protected networks in six minutes using Amazon EC2 compute power — an attack that would cost him $1.68. The key? Amazon's new cluster GPU instances. 'GPUs are (depending on the algorithm and the implementation) some hundred times faster compared to standard quad-core CPUs when it comes to brute forcing SHA-1 and MD,' Roth explained. GPU-assisted servers were previously available only in supercomputers and not to the public at large, according to Roth; that's changed with EC2. Among the questions Roth's research raises is, what role should Amazon and other public-cloud service providers play in preventing customers from using their services to commit crimes?"
"what role should Amazon and other public-cloud service providers play in preventing customers from using their services to commit crimes?"
The same role that Ford Motor Company is responsible to fill in preventing the use of it's vehicles as Getaway cars from scenes of crimes.
There's a spot in User Info for World of Warcraft account names? Really?
I wonder with the ways that WPA2-PSK is being eroded, if one should just go with 30+ character long keys. TrueCrypt always recommends to go with 20+ character passphrases and since there isn't much key strengthening with WPA2-PSK, a longer key is a good thing here. My preference is to use a 63 number of letters and digits, and if it gets forgotten, just generate another string and paste it into the router from a machine on the wired network.
Amazon provide infrastructure services. They need not, should not, must not know or seek to know how these services are used.
Oh wait, Wikileaks...
They who would give up an essential liberty for temporary security, deserve neither liberty or security - Ben Franklin
They should not take any steps in this direction. We should have learned that. it. just. don't. work. Brute-forcing a hash is not illegal anyway. If the customer of amazon decides to misuse the result, than this is not the responsibility of Amazon. Many services and tools can be abused for crime.
what role should Amazon and other public-cloud service providers play in preventing customers from using their services to commit crimes?"
No role whatsoever; let law enforcement agencies handle criminal investigations.
Palm trees and 8
Among the questions Roth's research raises is, what role should Amazon and other public-cloud service providers play in preventing customers from using their services to commit crimes?"
None whatsoever. Amazon and other service providers are retailers. They are not a police force. If a crime is being committed, let the designated authorities (i.e. cops) investigate it, police it, and arrest the criminal. No business should ever be involved in policing anything. That's a role specially held for the executive branch of governments.
Motorcycles, Robots, Space Gossip and More!
Probably because grandfathers tend not to be bitches.
How come you never age?
If you are going to troll like this try aging your character.
It's actually 20 random characters that are recommended for use as cryptographic keys. The reason for this is that 20 random keys from the US keyboard has the same number of possible combinations as 128 random bits. If you use anything less than 20 random characters, even if you use a 128-bit encryption algorithm, you won't have 128-bit encryption. The same is true if you use 20 non-random characters. A brute-force attack would try passwords with words or phrases before going for the really random stuff, so you again don't have 128bit encryption.
Also fun to realize: for every character less than 20, you lose 100x your security. A 19-character password could be cracked in just 1% of the time of a 20-character password. A 10-character password would take .000000000000000001% of the time.
A slashdotter who didn't build his own computer is like a Jedi who didn't build his own lightsaber.
"In the same amount of time" is the biggie. They are talking about using short timeslices of hundreds of computers. The article mentions using 400 GPUs (but isn't very clear on whether 400 GPUs for 20 minutes is what costs $1.68). If that's true, then decoding it with a single GPU would take about 5 1/2 days, assuming you had the same class of hardware Amazon is using.
Not earth-shattering amounts of time, true, but if speed is of the essence you probably don't want to wait the better part of a week.
"This post contains words, known to the State of California to cause thought. Wash brain thoroughly after reading."
I would expect Amazon to cooperate with the law enforcement should they discover that their service was abused to commit a crime. But why should they required to "avoid" it? And most of all, how? The only way to really keep people from using that service for criminal means would be to explicitly disallow certain uses and then monitor whether it is used this way. And that in turn raises a question: How? Because one of the core reasons this service is interesting is that it offers cheap calculation power. If you attach a metric ton of red tape and surveillance, it's most likely cheaper and faster to let your old Pentium do it.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Cloud services need to avoid any type of actions that create the illusion that they may be responsible for what users do. As long as they never have any editing of any uses of their product they will probably not be held liable by the courts. In a way it is like the truck driver that opens the trailer door and sees what he is delivering. As long as he does not know what is in the trailer the law will not charge him with transporting illegal or stolen items. Intent and knowledge are locked together. Don't look, don't see and don't know.
Not always.
Access points use the SSID as the salt, and most APs use common default SSIDs.
The basic story is slightly hysterical. Firstly, WPA2 does use a multiple-iteration key derivation function. Secondly, even with the claimed performance, he can only "brute force" five or six characters, depending on the character set in use. It's enough performance to deal with dictionary words, because, indeed, it's a dictionary attack. But even at 400K password derivations per second (ie 400M SHA-1 hashes per second), eight random characters drawn from the 96 character printable ASCII repertoire are going to take 571 years to perform a brute force attack on, or an average time to success of 285 years. Don't like the odds? My home network uses 12 characters drawn from a 64 character set (ie base 64 encoding), which needs 374 million years (average 167 million) at that performance. Do I give a shit if that number gets reduced by a few orders of magnitude? Not really: I can always move to 15 characters...
...should Amazon and other public-cloud service providers [be liable for] customers [...] using their services to commit crimes?
Hope this helps...
XKCD:Xeric Knowledge Comically Dispen
The assertion that high end Tesla cards (often $2k) are required for this crack is nonsense. In terms of integer, single precision floating point and memory bandwidth, a GTX 580 is actually FASTER than the most expensive Tesla card. Tesla cards have better QA for 24/7 usage, 4x faster double precision floating point, and 3 or 6 GB of memory, plus some other occasionally useful features. But anyone with an NVIDIA SLI gaming rig built in the last 2 years could easily have done what this guy did in less than 20 minutes.
Because human beings have two sexes, so we have to choose one?
Gamingmuseum.com: Give your 3D accelerator a rest.
The problem, as one of the referenced articles points out ans as has been known in the crypto-community for a long time, is fast key-derivation functions. Even the original UNIX password encryption function already took that into account and iterated the key derivation function to make attacks take longer. Typical methods used today for example iterate a second or so on the target CPU. This is a compromise between needing one second per unlock and requiring one second per brute-force attempt on an equivalent CPU. GPUs still make that attempt problemantic, but one application of SHA1 takes something like 0.1 microsecond on a modern CPU, so it should at least be iterated 10'000'000 times or so. Even with that, SHA1 is a bad choice, as it is too simple. Use something that requires a full-blown CPU to work and that a GPU cannot easily do. Of course, high-entropy passwords also help a lot by enlarging the search space.
But in essence, EC2 GPU instances can only break Crypto for cheap that was badly implemented anyways. That is not really a surprise. There are far too many people out there that do crypto without even understanding the attack possibility, let alone being cryptographers.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
People need to stop using non-random passwords for WPA2-PSK. This attack sounds like a dictionary attack, because there is no way at only 400k passwords per second that he could map more than a minuscule fraction of the 2^256 key keyspace. We are talking 1e77 potential passwords. At 400k/sec that only amounts to 1e13 passwords per year. It will still take 1e64 years to break. Since the universe is only ~1.5e10 years old, I think we are safe enough from a true brute force attack.
Of course that assumes people do turn off WEP and WPA1 and all the WPA1 crap in WPA2 (like turning off TKIP and only allowing CCMP).