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How crackers ransack passwords like “qeadzcwrsfxv1331”

arstechnica.com

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Re: How crackers ransack passwords like “qeadzcwrsfxv1331”

#61

Post by [deleted] »

markdown wrote: post #54
eropple wrote: post #45

Earlier quoted context omitted.

"Pepper"s are essentially meaningless and provide no real benefit over a salt. And you should be using bcrypt anyway.

> "Pepper"s are essentially meaningless and provide no real benefit over a salt. Citation needed. There appears to be a case where it could prove to be an advantage: http://security.stackexchange.com/questions/3272/password-ha... > And you should be using bcrypt anyway. Yeah, except bcrypt isn't always an option. Eg: on Google App Engine.

[deleted]

Re: How crackers ransack passwords like “qeadzcwrsfxv1331”

#62

Post by skavander »

reeses wrote: post #47
tomku wrote: post #22

Earlier quoted context omitted.

Maybe we read different articles, but the one I read seemed intent on strongly downplaying the amount of extra security that salting provides. It actually uses the phrase "minimal amount of protection" to describe a salt's effect on cracking attempts. That seems like a strange choice of words when salting would've completely changed the outcome of the cracking attempts described in the article. Edit: To be clear, I'm…

Salting wouldn't have changed the outcome of the cracking attempts in the article. The primary focus was on how pre-computed hashes (rainbow tables, etc.) are no longer a tool used by most people attacking password lists because GPU-based hashers are efficient enough, the dicts long enough, and the methods of permuting the dicts (combinations, leet substitutions, markov chains, etc.) are rich enough that storing all…

Every time figure quoted in the article (eg "Retrieved 2700 passwords in 2 minutes 30 seconds") would have been up to 16,000x larger if a salt had been used since a separate hash would need to be computed for each password rather than just one hash to compare to all 16,000 passwords. 2.5 minutes x 16,000 would be around 28 days to compute the "first pass" alone.. much less feasible, especially as the parts that took multiple hours would take several years to finish. It's true you could still crack the same percentage of passwords eventually, but being able to crack 90% in 5 years or in 20 hours is a very different outcome.

Re: How crackers ransack passwords like “qeadzcwrsfxv1331”

#63

Post by nknighthb »

chongli wrote: post #35
nknighthb wrote: post #34

Earlier quoted context omitted.

If the contents of the device can be dumped, the problem remains. If not, you have no copies of your database, so when (not if) the device or the server it's connected to fails, your site is down, and once you've brought it back up, all of your users must go through a password reset process. That one server/device is now a single point of failure and a bottleneck in processing logins. You're also still relying on the…

I didn't say anything about reliability or single points of failure. I merely pointed out that it was possible to separate the salt from the hashes and gain security that way. Whether this is practical or not depends on how important security is to you. And yes, it would not be possible to dump the contents of the devices.

The proposal is fundamentally impractical, and thus not a "security gain" in any meaningful sense. It's the equivalent of preventing cipher algorithm breaks by using nothing but one-time pads.

It's also theoretically impure in any case, as you've done nothing but add an additional peripheral to the computer. You're seeking obfuscation, not real cryptographic integrity.

Re: How crackers ransack passwords like “qeadzcwrsfxv1331”

#64

Post by _ikke_ »

jevin wrote: post #26
grecy wrote: post #5

Earlier quoted context omitted.

> the MD5 case they present is a poor case If guys using vanilla hardware get that kind of success in 1 hour with MD5, you only need to increase hardware and the time required to see it's still completely doable for other hash functions.

That's why the Blowfish algorithm is the best choice for password hashing. The algorithm uses CPU cycles to generate the hash. So there is no way to speed it up, just by using a faster computer.

A faster computer does speed it up. It can go through all the cycles faster.

An even better option is scrypt, which is memory based, which is much harder to scale.

Re: How crackers ransack passwords like “qeadzcwrsfxv1331”

#65

Post by sirclueless »

knightsamar wrote: post #51

How about passwords not English words but written using Latin alphabet ? Like mer@s@nket!k$habd (Hindi for "my password") ? Bet that would be harder to crack and still easier to remember for a multi-lingual person. In fact if non-latin alphabet is widely supported for entering password, it would make them a bit more secure I feel.

Yes, the non-latin alphabet in particular probably helps a great deal, if you use a substantial portion of it. The Hindi words probably less so, since they are just as likely to end up in dictionaries of common password fragments.

Re: How crackers ransack passwords like “qeadzcwrsfxv1331”

#66

Post by wfn »

chongli wrote: post #31
nknighthb wrote: post #23

Earlier quoted context omitted.

The server must have access to both the salt and the hash to verify a password. Therefore, upon compromise of the server, the attacker automatically has access to both the salt and the hash. There is no way around this problem that isn't simply obfuscation.

Not necessarily. With something like a smartcard or TPM chip, one could move the hashes and salts off the server. Both would still be stored together (on the device) but they'd be separate from the server! Edit: Or one could move just the salts into the device and store an index into them in the password file. Hashing would be carried out by the device but an attacker would only gain access to the indices. Without st…

Hm. I suppose a hacky-ugly-cheapo way to do this would be to run a daemon under root which accesses a local sqlite db or whatnot (and that file is only reachable by root). When a web/whatever app needs to check a hash, it asks the daemon whether this user + this hash are valid. This could be done e.g. using unix sockets, and the daemon could do rate limiting (one attempt per two seconds for a specific user, etc). The exchange could also be encrypted using a pre-defined key, so having access to the socket wouldn't even let you sniff the exchange.

If a cracker gets access to the web app, they'll be able to monitor the exchange, but they'll need actual privilege escalation to be able to read/dump the whole hash database.

Re: How crackers ransack passwords like “qeadzcwrsfxv1331”

#67

Post by xioxox »

knightsamar wrote: post #51

How about passwords not English words but written using Latin alphabet ? Like mer@s@nket!k$habd (Hindi for "my password") ? Bet that would be harder to crack and still easier to remember for a multi-lingual person. In fact if non-latin alphabet is widely supported for entering password, it would make them a bit more secure I feel.

It's dangerous to choose anything someone else might choose. My favourite technique for good passwords is to think of a memorable phrase (preferably with numbers) and take the initial letter of each word.

"I can sleep at Nandos, providing I pay $100 for that"

Ics@N,pIp$100ft

Re: How crackers ransack passwords like “qeadzcwrsfxv1331”

#68

Post by smartwater »

gizzlon wrote: post #46
davedx wrote: post #41

Earlier quoted context omitted.

If it's a specialised rig then it'll only be good for MD5 I think. Most sensible websites don't use MD5 anymore.

Most sensible websites don't use MD5 anymore What makes you say that? Do you mean new sites or all site? Got anything to back it up? I would guess most sites in existence use MD5, SHA1 or similar with 1 round, because it was (is?) very popular.

Bitcoin rigs are only good for certain mathematical functions. They are not general computing devices.

Re: How crackers ransack passwords like “qeadzcwrsfxv1331”

#69

Post by mikegioia »

csense wrote: post #60
_b8r0 wrote: post #55

Earlier quoted context omitted.

I'm in the middle of researching re-evaluating rainbow table attacks in light of Moore's law, GPUs and Crack (lookup) tables, I've also looked into countermeasures. What you're describing is partially correct. When you crack passwords (either with rainbow tables or by brute force) you generate an iterator or use a dictionary and work through this generating hashes (with rainbow tables this works via a series (or chai…

What if a site uses 128-bit salts generated by a good (perhaps hardware-based) RNG?

That will remove pre-computed rainbow tables from the equation.

Re: How crackers ransack passwords like “qeadzcwrsfxv1331”

#70

Post by JDGM »

oskarth wrote: post #40

Cue a test-how-strong-your-password-is service where security conscious individuals can test how their particular password stands up against these new attacks.

It's not really what you described, but this is quite jolly: https://howsecureismypassword.net.
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