Eight RTX 4090s Can Break Passwords in Under an Hour

https://www.tomshardware.com/news/eight-rtx-4090s-can-break-passwords-in-under-an-hour

by danboarder • 4 years ago

31 21 4 years ago

raydiatian• 4 years ago

So what’s the new benchmark for safe password length? I’ve been at 24 random characters for awhile, is this too short for HashCat?

chick3nman2• 4 years ago

The math says 12+ if randomly generated by something like a password manager and including uppercase, lowercase, numbers, and symbols. 95^12 is too big for pretty much anyone to crack for a very long time, if ever. There is a small caveat to this regarding what type of hashing is being used though. In nearly all cases, even in the case of relatively weak hashes, 12+ is enough, but there are hashes which truncate or break up inputs. Windows LanMan(LM) is probably the most common offender still seen these days that does this and any LM will always be breakable up to 14 characters due to its underlying algorithm leading to a weak separation of 7 + 7 characters. In the case of Windows hashing a default length of 15+ can help to avoid LM being stored but for legacy systems it may be unavoidable.

naikrovek• 4 years ago

I don't think the NTLM thing of 7+7 has been true since Windows 2000 and the introduction of Active Directory.

it's been a long time, I know that.

MontyCarloHall• 4 years ago

It says 300 Gh/s for NTLM and 200 kh/s for bcrypt.

There are 62^12≈10^21 12 character mixed case alphanumeric passwords. At 3*10^11 hashes/second, this would take ~3*10^9 seconds (~100 years) to brute force. For bcrypt, an 8 character password is fine (it would take ~30 years to brute force). Of course, you have no idea what hash function a breached site may have used, so best to err on the side of caution.

That said, avoiding password reuse is far more important than the strength of an individual password (not that it’s unimportant). The vast majority of breaches occur due to credential stuffing attacks on other logins, not from the initial breach itself.

efficax• 4 years ago

if you're using all valid characters (numbers, punctuation, upper and lowercase, etc) then every extra character grows the set of possible passwords exponentially, not linearly. 24 characters is a huge problem space, i don't know exactly how many possible characters there are but let's say it's 50, so that's 50^24 which is 41 digit number, a number so big I don't know what to call it and still in the realm of a password that would take so long to crack you would die before it was finished cracking.

hn_go_brrrrr• 4 years ago

50^24 is roughly 59.6 duodecillion, if you were curious.

jqpabc1233• 4 years ago

How do you fix this? Quite easy really --- simply limit the number of unsuccessful attempts before locking the account --- either temporarily or indefinitely.

Most security focused web sites do this now.

hotpotamus• 4 years ago

You're thinking of brute force attempts over the network which are very slow and as you mention should be subject to tarpits and lockouts. This is if you can get your hands on the hashed passwords; I would think a GPU cluster can do something from millions to trillions of attempts per second depending on the algorithm.

jqpabc1233• 4 years ago

Here is my hashed password: Gx5jp2z8,h

Let me know when it has been succesfully decrypted. Or better yet, explain how you can possibly know if a decryption is succesful except by testing it.

You can make 10 test attempts before you're locked out for 1 hour. Another 10 attempts before the account is locked indefinitely.

The number of attempts per second your GPU cluster can make is no longer relevant.

lakomen• 4 years ago

There is no mention of how long those passwords are so for me this is clickbait

shellfishgene• 4 years ago

Article: "The researchers estimate that a purpose-built password hashing rig (pairing eight RTX 4090 GPUs) could crack an eight-character password in 48 minutes."

virodoran• 4 years ago

For further clarity, this is for NTLM hashes. And the entire article is indeed clickbait and considering the numbers they're referencing, they likely came from this tweet [1] which the article doesn't link as a source at all.

[1] https://twitter.com/tinkersec/status/1580722789245280257

Eight RTX 4090s Can Break Passwords in Under an Hour

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