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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?
cracking an encryption key is not a crime. Using a cracked encryption key to seal data is a crime, and that hasn't changed.
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
From the article:
"This approach is so easy a grandmother could use it"
As a 49 yo grandmother, feminist, and C programmer I find that offensive. Why not a grandfather ?
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.
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How much time does this take to do on a home computer using the same GPU acceleration? I know that Amazon has tons of computing power, but you're not the only one using it. Why spend $1.68 to crack a key when I can do it for free in the same amount of time on the PC I already have.
They cannot arguably be capable of defining what actions being taken with an EC2 instance are and are not crimes, therefore they should not even attempt to do so. It is not, after all, their duty to do so.
They can refuse service to those who they feel are suspicious, or cut people off if they violate some generic ToS, but surreptitiously cutting in because they think someone is committing a crime (and cracking WPA is not a crime), only runs them the risk of false positives.
More importantly, if they really feel they are observing someone committing a crime using their service, they should stand back and report it to authorities, who (in varying degrees of accuracy) are charged with being capable of determining if a crime is taking place and have the authority to intercede.
You can buy computer time to compute things! What will they think of next!
Breaking news! Tools can be used for anything!
Do you require pre-approval to use a hammer since it can be used to kill someone? What about the knives in your house?
Just like the phone company they should pay no attention to what their systems are being used for.
Trying to police it is a waste of resources. They start looking then people will start obfuscating the data. If I send you a big pile of data in no noticeable format (since I've grabbed only the stuff I need and catted it together) and a bunch of code it's going to take you a lot longer than 6 minutes to figure out what it does. Once you do figure it out then what's the point work has already been done?
I find being offended by me offensive.
Tell that to Napster.
I'm not certain how Amazon would be able to prevent such activity before it happened, aside from code snooping, which is probably in violation of the terms of their services agreement. Perhaps profiling would be in order before accepting someone as a customer, but how would you protect yourself against shell companies acting on behalf of a known abuser? Rather, I think the question should be "how quickly can Amazon react when this occurs".
ISP's and hosting providers have had to face similar situations for almost a couple decades now, and I would think that they'd be the logical entities for Amazon to consult with re: the mitigation of illegal activities using their cloud as an attack vector.
Rule #1 -- Politics always trumps technology.
It's not a crime the same way that picking locks isn't a crime. But that doesn't mean that if you're the one picking the locks that the cops are going to consider you an innocent bystander either. Legally, Amazon might be in the right for looking the other way as people do this, but that doesn't mean that they aren't going to suffer the consequences when/if somebody uses their equipment to break the law.
Someone took a password-guessing program and ran it on EC2. Big freaking deal.
EC2 now offers GPUs. Someone took a GPU-based password-guessing program and ran it on EC2. Big freaking deal.
True, raw SHA-1 used all by itself is not the thing to generate password hashes with, but this is not a weakness in SHA-1. As the researcher says, it shows merely that SHA-1 is efficient.
SHA-1 is not weakened, broken, or exploited in this research (it is significantly broken in other ways though).
Teams were guessing passwords with GPUs Defcon last year. They were guessing passwords with EC2 last year, too. The combination is not novel or innovative.
This reads like Marketing placement to me.
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.
Amazon doesn't know what the computations taking place on the CPUs/GPUs they lease are doing.
They could be searching for oil deposits, searching for radio signals from ET, recovering lost keys for a legitimate owner, for law enforcement, or for bad guys. They could be doing several of those things simultaneously and it would take very time consuming, deep, by-hand expert research to try to figure it out and you'd still never be sure you understand what all the numbers mean.
Amazon probably doesn't even know when someone installs a web server or a database on an EC2 node. They certainly don't know whether or not it's used to host material leaked from govt sources legitimately into the public domain or who and who isn't a journalist.
That doesn't seem to stop them from selectively applying their ToS at the request of the likes of Sen. Lieberman.
Excuse me? Since when is the maker of a tool liable for its misuse? Did they change a law when I, Smith and Wesson were not looking?
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Oh, about 6 seconds for that security travesty, I reckon. 4 seconds, if setup by faulty Windows Admins.
HA! Mr. T is still laughing at you, only harder this time.
This is the NSA, we're gonna geet U h@x0r5! Also, what is a h@x0r5?
Every time we talk about sensible law someone comes in with a counter example out of the area of copyright and patents.
Please, in case you haven't noticed yet, the insanity in copyright and patent laws is only rivaled by sex laws. Let's hope at least the rest of the legal codex at least retains a bit of reason and connection to reality.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Either the guy is lying or the pricing is wrong, from the TFA is says they charge 28 cents a min, but from the amazon ec2 pricing page it says [quote]Pricing is per instance-hour consumed for each instance, from the time an instance is launched until it is terminated. Each partial instance-hour consumed will be billed as a full hour.[/quote]
also to get 28 cents/min you would need to run 8 instances at $2.10/hour so really he paid $16.80 not $1.68
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.
... is not a crime!
"Alcohol, Tobacco, Firearms, and Explosives" should be a convenience store, not a government agency.
Reason is the key you provide isn't used directly on a competent cryptosystem. It takes a hash of the key. So the key is always the requisite number of bits for the system, even if it is actually too long or too short.
Now you are correct in that shorter keys are faster to crack, however in a system like that you can't just straight out brute force the raw keys. You have to take the passwords, hash them, then test that. That takes longer.
They certainly don't know whether or not it's used to host material leaked from govt sources legitimately into the public domain or who and who isn't a journalist.
They don't, unless that customer trumpets their use of the service in that manner to the world...
WPA is obsolete and has been. Use WPA2.
One simple solution I can see for this is forcing a certain amount of up time on the servers to avoid charges that make short-use less desirable. An example - if I want to spin up multiple parallel servers for 1 hour each, I can get 10 servers for a few dollars. That's a blink in terms of usage, but a lot of power for a short time - there's IO, provisioning, transfer, Etc., and real costs incurred on Amazon's side of things - and in terms of payback, Amazon probably makes more money if those 10 servers stay online for at least a couple-hours each. If someone makes a server run for short burns, they could employ a simple grace system - you get 4 systems an hour, and then get charged $1 for each create/shut performed unless the systems stay up in excess of 4 hours. This way, folks can feel their way in as newbs without taking a hit, but abuses could then pay a premium for doing things with behaviors that appear to be more malicious than kindly. Something along those lines could curb abuse - but I must agree with other folks' posting to some extent - it's not Amazon's place to enforce proper Internet behavior. Profiting from a slightly less abusable pricing model is probably the way to go - as long as they don't kill their customers or send business away.
That's a very good point.
I tend to think of someone's use of EC2 as public info, only a "whois" away.
Security researchers like to use EC2 because it's cheap, and it's hard to block network scans from since it shares a netblock with other mission-critical stuff like, say, Twitter.
It's likely that industry journalists would have made a big deal about Wikileaks using it had they not pointed it out themselves.
I still can't tell if this is a keyword placement-piece for EC2 or if somebody really does think this is novel research. ISTR hearing there is an upcoming BlackHat presentation (and that BlackHat was owned by a media company too).
Amazon ought to be extremely careful about playing politics with its ToS and safe harbor provisions.
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
it's hard to block network scans from since it shares a netblock with other mission-critical stuff like, say, Twitter .
OMGWTFBBQROFL!
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
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.
Make it illegal, and people will stop doing it.
That notion has universal appeal. It is simple enough that practically all voters understand it. It is compatible with most people's moral code, at least in principle. It lends itself very easily to law-and-order populism and electioneering, and of course anything that increases the use of police forces and prisons is popular with several major lobbying organizations. One problem, though: it only occasionally works. This is aside from any legal and civil rights issues associated with assigning liability to providers of goods and services who have no practical or conspiratorial relationship with the law breakers, and cannot easily be demonstrated to have shown negligence. Can anyone point out clearly relevant court precedent?
According to the back of this envelope, an eight digit upper case alphabetic key would take a worst case of $2436.32 for his algorithm to crack. What sort of shitty pre-shared key is he attacking? Or is my envelope wrong and I suck?
They whose government reduces their essential liberties for temporary security, receive neither liberty nor security.
Are you offering to bankroll an upgrade to all deployed products whose WLAN hardware lacks WPA2 support? I didn't think so.
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).
A lot of people have a very hard time with inductive reasoning, so they don't easily arrive at a general concept. Here, the general concept is that most useful tools can also be abused for malicious purposes. Each instance of this general concept makes news headlines for some reason. Usually it then splits into the usual "us vs. them" set of two camps: one calling for something to be banned or restricted or monitored, the other explaining why this is a generally unwise policy that amounts to a knee-jerk response to news that should not surprise anyone.
Henry David Thoreau explained it quite well (emphasis added):
And I am sure that I never read any memorable news in a newspaper. If we read of one man robbed, or murdered, or killed by accident, or one house burned, or one vessel wrecked, or one steamboat blown up, or one cow run over on the Western Railroad, or one mad dog killed, or one lot of grasshoppers in the winter, -- we never need read of another. One is enough. If you are acquainted with the principle, what do you care for a myriad instances and applications? To a philosopher all news, as it is called, is gossip, and they who edit and read it are old women over their tea. Yet not a few are greedy after gossip.
It is a miracle that curiosity survives formal education. - Einstein
Well, to be fair, your friends Smith and Wesson have a special exception just for them from any liability of any kind. However, fundamentally, you're correct. :)
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Where's the mobile app?
"In a 32-bit world, you're a 2-bit user. You've got your own newsgroup, alt.total.loser." -Weird Al
(shameless plug) Here is his talk description, and his materials will be on-line next week after this talk. https://www.blackhat.com/html/bh-dc-11/bh-dc-11-briefings.html#Roth
with 400K per seconde het could only crack a password of 5 - 6 position.
Checking on WPA-PSK , you will see that the password via some hash function results in 256 bits key. to to check all effective passwords at 400K/sec = 9,2 * 1-^ 63 year, that is considerable more than your guess...
So, I could not have done the same. You probably can't do it while on the road.
The beauty of using a cloud service is that, given the proper tools, your local complexity is down to having said tool sniff data, you enter EC2 credentials & maximum cost and off you go.
WPA-PSK is insufficiently secure... and it's Amazon's fault? Stupid. Did they crack https? No. So clearly there are sufficiently secure technologies. Use them. Don't prop up crap technologies by calling in the Feds. Honestly, invoking the law to resolve a problem that clearly doesn't require it is an actively dangerous habit of thought. And I'm hardly a libertarian. I just know a bad idea when I see one.
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I've heard ballpark guesses of around 10 years of work on a top supercomputer.
"When information is power, privacy is freedom" - Jah-Wren Ryel
Interesting comparison.
I, too, see the irony in the "dual-use" nature of technology in general, but I do have a perspective different than one thing you said though:
I've been to a bunch of hacker cons in the last couple of years and met a bunch of people in the infosec community. There are a lot of people using password guessing and other security auditing tools.
My impression is that, by far, the biggest users of these tools are organizations auditing their own security or contracting with outside parties to do so. Security auditing tools is a burgeoning industry and professional pentesters are in high demand. There are still a lot of black-tshirt-wearing hackers at the cons these days but if you talk to them most of them are in industry or government :-).
It's simply not correct to equate password-cracking tools with malicious purposes.
We had an employee who got sacked for using his network privileges to steal information from people. He then proceeded to try to hack our network and then use an EC2 instance to just and DOS attack us. I'm sure it's cheaper than a VPS solution from 5+ years ago but there has always been options for fucking with people. Using an EC2 instance is just another option. It could go away and they'd find something else.
I'm just glad we can get something like EC2 these days for those of us that want to do something legit.
Interesting comparison.
I, too, see the irony in the "dual-use" nature of technology in general, but I do have a perspective different than one thing you said though:
I've been to a bunch of hacker cons in the last couple of years and met a bunch of people in the infosec community. There are a lot of people using password guessing and other security auditing tools.
My impression is that, by far, the biggest users of these tools are organizations auditing their own security or contracting with outside parties to do so. Security auditing tools is a burgeoning industry and professional pentesters are in high demand. There are still a lot of black-tshirt-wearing hackers at the cons these days but if you talk to them most of them are in industry or government :-).
It's simply not correct to equate password-cracking tools with malicious purposes.
Sure, just like a claw hammer could be misused as a murder weapon, yet the vast majority of people using claw hammers are only interested in driving nails. That's about how I would summarize the situation with password cracking tools. Note I never claimed they are primarily used for malicious purposes, only that overreacting to their potential malicious uses is unwise.
If the media treated claw hammers the same way they treat anything related to computers and networks, then every time some psychopath bludgeoned someone to death with a claw hammer there'd be big discussions about whether hammers need to be banned, or whether you should have to present ID to purchase one, or whether hammer manufacturers have a responsibility. The double standard and the phony shock at discovering that yet another tool can be abused is what I find absurd.
It is a miracle that curiosity survives formal education. - Einstein
If Amazon's GPU clusters are this cheap and easy & can be used for this, what other encryption can they be used to break? My PGP encrypted hard disk for $9.95? Then again, maybe my concerns are unfounded. Maybe someone can explain where I missed the boat?
a friend explained to me when I was off track. Oh well.