Comment by mr_mitm | Hacker News Reader

Comment by mr_mitm | Hacker News Reader

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It really annoys me how everyone takes that statement that a 20 character password has been cracked at face value. If it was randomly generated, it is physically impossible to crack even if it was hashed with MD5. It's also unlikely that somebody memorized 20 random characters. It is much more likely that the passphrase was weak because it's the title of a Wikipedia article or contained in some public word list.

Also, by going with the original article (https://nantes.indymedia.org/posts/87395/une-lettre-divan-en...), which I translated using DeepL, this is what we know:

> As far as the investigation is concerned, in recent months new elements have been added to the file. The most significant is that the police managed to gain access to my computers, even though they were encrypted. The one at work, on which Windows is installed, is encrypted with BitLocker. _A previous report in the file says that they had already tried to access it while I was in police custody but had not succeeded._ But in September the Brigade d'appui en téléphonie, cyber-investigation et analyse criminelle (BATCIAC) sent a copy of the hard disk to the SDAT. In the PV, they only explain that they booted the computer with a bootable USB key and then used the software AccesData FTK imager 3.3.05 to copy the hard disk. But they don't talk about the decryption itself.

> My personal computer, which runs Ubuntu 18, is encrypted with Luks (the password is more than twenty characters: letters, numbers, punctuation marks...). I couldn't find any indication in the file about how they decrypted it, but there too they made a copy of the hard disk. There are even files that had been deleted and emails that had been downloaded with Thunderbird (and then deleted). They didn't find anything that could be related to the fires I'm charged with. But I think the very fact that they were able to access hard drives encrypted with supposedly unbreakable software should be made as widely known as possible.

This clearly hints at an evil maid attack, which we always knew were a real risk when it comes to full disk encryption.

He says his BitLocker drive was on a work computer. If it was managed through Active Directory then those key may have been recoverable through his employer.

https://learn.microsoft.com/en-us/windows/security/informati...

There used to be a bug where bitlocker would rely on the firmware's encryption functionality if it was there, and there were cases of firmware with a literal "if checkpasswd () then"... overwrite that check to true and you're in.

Soif it concerned a disk with that vulnerability, maybe they did it like that.

(See https://www.ieee-security.org/TC/SP2019/papers/310.pdf)

Little backdoors

Why would they do an evil maid attack on the Ubuntu laptop, but not at the same time on the Windows one?

And is there any information that they accessed the Ubuntu laptop before he was arrested (to do the evil maid attack)? I see no mention of that.

I think it's much more likely that it was a weak password, maybe even partially shared with other passwords. Maybe police obtained user passwords from other low value targets (online shops, ...), looked at them and noticed a pattern.

> There are even files that had been deleted and emails that had been downloaded with Thunderbird (and then deleted).

This doesn't mean much, unless user didn't know that when you delete a file it's content is not actually scrubbed from storage.

Thanks! Reading the article, I was already wondering myself: Do we already know any of this for fact, or is this just more wild mass guessing?

The article doesn't seem to cite any new sources other than people speculating on twitter/mastodon. Following down the social media rabbit hole, I end up back at the article that sparked the debate 5 days ago. Some RFCs and product data sheets are cited to support the back-on-the-napkin calculations (also cited from social media), but do we have any credible source yet to confirm that's what really happened here?

Until we know his password, we can't know for certain. "Fuck the police!2023" fits the description of the password but it's hardly unguessable.

All we know is the authorities gained access to his drive's key. We probably won't find out how they did it until his trial starts.

Well, we also know they didn't crack a random 20 character password. But some people appear to be panicking as if they did.

You know this because you think it is mathematically impossible?

Not mathematically, but physically. You need astronomical quantities of energy. Bruce Schneier pointed this out in "Applied Cryptography" (1996):

https://www.schneier.com/blog/archives/2009/09/the_doghouse_... (unfortunately the exponents are not displayed correctly here)

> One of the consequences of the second law of thermodynamics is that a certain amount of energy is necessary to represent information. To record a single bit by changing the state of a system requires an amount of energy no less than kT, where T is the absolute temperature of the system and k is the Boltzman constant. (Stick with me; the physics lesson is almost over.)

>Given that k = 1.38×10-16 erg/°Kelvin, and that the ambient temperature of the universe is 3.2°Kelvin, an ideal computer running at 3.2°K would consume 4.4×10-16 ergs every time it set or cleared a bit. To run a computer any colder than the cosmic background radiation would require extra energy to run a heat pump.

>Now, the annual energy output of our sun is about 1.21×1041 ergs. This is enough to power about 2.7×1056 single bit changes on our ideal computer; enough state changes to put a 187-bit counter through all its values. If we built a Dyson sphere around the sun and captured all its energy for 32 years, without any loss, we could power a computer to count up to 2192. Of course, it wouldn’t have the energy left over to perform any useful calculations with this counter.

>But that’s just one star, and a measly one at that. A typical supernova releases something like 1051 ergs. (About a hundred times as much energy would be released in the form of neutrinos, but let them go for now.) If all of this energy could be channeled into a single orgy of computation, a 219-bit counter could be cycled through all of its states.

>These numbers have nothing to do with the technology of the devices; they are the maximums that thermodynamics will allow. And they strongly imply that brute-force attacks against 256-bit keys will be infeasible until computers are built from something other than matter and occupy something other than space.

I’m not sure how we go from 20 character string to 256 bits? Guessing the 20 character string is a lot more likely than cycling through every state of a 256 bit key.

They could have gotten lucky of course.

Yeah this person is saying “impossible” when they mean “extremely improbable.”

Let's just say the probability is negligible.

At some level it's extremely likely that this is all that ever needs to be done, even if the password needed to be cracked is 300 characters long and completely random. The likely case is that this password is in a password vault, which is either 1) online managed by a company (in which it's easy to see that it's inevitable to be leaked or cracked, given the news we've seen from these companies) or 2) it's on a local device and still has a simple password to get access to all passwords. It's extremely unlikely that someone has a completely random password that is >40 characters long for the password manager.

> It's also unlikely that somebody memorized 20 random characters.

I routinely memorized 15 character random passwords until I switched to bitwarden, 20 doesn't seem out of bounds. Now, with bitwarden, I have no idea what any of my passwords are.

I did this too, now i generate a random pwd long as hell and i do a pwd recovery when i have to log-in so i don’t have to store them anywhere. My master pwd is my email pwd based on a mail server i operate. Yes paranoid is my second name.

So now you only memorize one 15 character random password for your bitwarden, is this the way to go? I am new to password managers.

That’s the idea yeah - you have one long high entropy password that you use to unlock all your others. Then you only need to remember one thing.

In my case, this isn’t my literal password, but it’s very similar to: “These420HugeWhiteBadgers1984” Which is secure enough, easy to enter, and easy to remember.

> even if it was hashed with MD5

This is what I don't understand about articles like this. Say we're using a cryptographic hash to generate the password from even a commonplace phrase. Typically you will have thousands of random bits in the hash and you can grab a uint64 (or even a uint128 if you want) from anywhere in that (theoretically uniformly distributed) set of bits. Is that not a random point in a 2^64 (2^128) space?

No, because in that entire space, only eg. 62^20 would be used, and that's a much smaller space. There are various techniques to focus on that subset of the space.

I agree with taking this with a grain of salt, but i'm not sure how "this clearly hints at an evil maid attack". At this point anything is pure speculation: evil maid or other pre-seizure compromise, some amount of password guessing, exploit in some of the software, secret extraction from hardware, ...

> the password is more than twenty characters: letters, numbers, punctuation marks

Was it random, though?

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