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My USB Drive Has a Hidden Encrypted Vault

rootkitlabs.com

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Re: My USB Drive Has a Hidden Encrypted Vault

#41

Post by Retr0id »

There are other issues with AES-CTR - an attacker can flip bits at chosen offsets in the plaintext without knowing the key. For example, if they know (or can guess/infer) what offset the relevant portion of the `sudo` binary is at, they could flip the branch instruction responsible for password checking. This can be done in one step, as opposed to the multi-step plaintext recovery attack described in the article.

With XTS, the attacker is forced to completely garble a whole block at a time.

Re: My USB Drive Has a Hidden Encrypted Vault

#42

Post by fhdkweig »

monster_truck wrote: post #24
fhdkweig wrote: post #12

Earlier quoted context omitted.

Be careful in countries like UK which have laws requiring the decryption of any data they find. There are people sitting in jail because they couldn't decrypt the "random noise" on their computers.

There literally are not. Anyone competent enough to be an expert witness will be able to plainly explain to everyone else how statistical analysis obviously delinates the difference between truly random noise and an encrypted volume.

Even if that is true, I have better things to do with my time and money than pay a expert witness to explain: see, I wasn't breaking the law, I just wanted the cops to think I did. That just seems like a really bad idea.

Re: My USB Drive Has a Hidden Encrypted Vault

#43

Post by Dylan16807 »

tptacek wrote: post #3

If you're using off-the-shelf "hidden" encrypted volume schemes, you're not going to be evading state-level adversaries; if you can find these projects and conveniently use them, state vendors can and will write scanners that find them. They're paid to do it; new detections are how they get to charge for maintenance and new versions. Then you're down to two issues: (1) Concealing an encrypted volume jacks suspicion w…

You can compensate for not just 50x but 500x by adding 2 characters to your password. If that's the speedup factor, it's not itself a big worry.

Re: My USB Drive Has a Hidden Encrypted Vault

#44

Post by rectang »

tptacek wrote: post #30
aeturnum wrote: post #28

Earlier quoted context omitted.

I often see comments like this on encryption related project. Depending on the reader you make what might be an essential point - but I also don't really know how useful it is to say it here. The author makes no claims about what adversaries this should be sufficient against and is completely open about their constraints and decisions (allowing you to make the critique in the first place). Basically evading a state-l…

I'm generally pretty fatalistic about avoiding state-level adversaries. So, in a sense, it doesn't really matter how one thinks a security countermeasure is going to stack up against an IC attacker. The important thing is that people understand how hard this is to do, and take that into consideration before adopting tools like these. You can easily make things worse for yourself. I think this post is a fun technical…

A while ago I participated in security design for an open source foundation. (Security is not a specialty of mine, but I aspire to be competent enough for my role as a developer working in web dev and open source.) We attempted to design our processes to assure some level of defense against state-level threat actors despite assuming we could not keep them out of our network. The main goal was to ensure an audit trail in the event that our source repositories or release archives were compromised and changed.

Re: My USB Drive Has a Hidden Encrypted Vault

#45

Post by tptacek »

Dylan16807 wrote: post #43
tptacek wrote: post #3

If you're using off-the-shelf "hidden" encrypted volume schemes, you're not going to be evading state-level adversaries; if you can find these projects and conveniently use them, state vendors can and will write scanners that find them. They're paid to do it; new detections are how they get to charge for maintenance and new versions. Then you're down to two issues: (1) Concealing an encrypted volume jacks suspicion w…

You can compensate for not just 50x but 500x by adding 2 characters to your password. If that's the speedup factor, it's not itself a big worry.

You can eliminate the problem entirely by using a random full-allowed-character-set password. The whole point of KDFs is that the password/passphrase is predictable (usually: by being generated from a seed dictionary).

Re: My USB Drive Has a Hidden Encrypted Vault

#46

Post by Dylan16807 »

tptacek wrote: post #45
Dylan16807 wrote: post #43

Earlier quoted context omitted.

You can compensate for not just 50x but 500x by adding 2 characters to your password. If that's the speedup factor, it's not itself a big worry.

You can eliminate the problem entirely by using a random full-allowed-character-set password. The whole point of KDFs is that the password/passphrase is predictable (usually: by being generated from a seed dictionary).

Random is important, character set not so much. And yes when I say 2 characters I mean random ones. Even 26x26 is plenty to compensate. Or you can add one random word.

Re: My USB Drive Has a Hidden Encrypted Vault

#47

Post by jandrese »

Retr0id wrote: post #6
tptacek wrote: post #3

If you're using off-the-shelf "hidden" encrypted volume schemes, you're not going to be evading state-level adversaries; if you can find these projects and conveniently use them, state vendors can and will write scanners that find them. They're paid to do it; new detections are how they get to charge for maintenance and new versions. Then you're down to two issues: (1) Concealing an encrypted volume jacks suspicion w…

> If you're using off-the-shelf "hidden" encrypted volume schemes, you're not going to be evading state-level adversaries; I kinda assumed this was a solved problem now, up to the information-theoretic limit. Just create a FAT32 fs (for example), put some boring decoy files on it, and then unmount it. Traverse the FAT to map which blocks are in-use vs not-in-use, and use the not-in-use ones to store your encrypted da…

Doesn't FAT have the concept of "badblocks" to handle the old days when sectors could randomly fail on drives and they had to work around it? It would only be slightly more suspicious but it would allow the drive to be mounted and used as a regular drive to avoid the even more suspicious unmounted volume issue. The data in the sectors would obviously be encrypted so it looks like random noise if someone does start poking around looking at it.

Re: My USB Drive Has a Hidden Encrypted Vault

#48

Post by tptacek »

ninju wrote: post #39
tptacek wrote: post #32

Earlier quoted context omitted.

Can you check again and share where you're getting that number?

It may have gotten cheaper https://prodefence.io/news/pegasus-spyware-operating-costs-c...

Thanks! Per-seat licensing here checks out.

Re: My USB Drive Has a Hidden Encrypted Vault

#49

Post by tptacek »

Dylan16807 wrote: post #46
tptacek wrote: post #45

Earlier quoted context omitted.

You can eliminate the problem entirely by using a random full-allowed-character-set password. The whole point of KDFs is that the password/passphrase is predictable (usually: by being generated from a seed dictionary).

Random is important, character set not so much. And yes when I say 2 characters I mean random ones. Even 26x26 is plenty to compensate. Or you can add one random word.

We're both saying the same thing: you can make the KDF irrelevant if you (as you just specified) use an AES key as an input. The entire point of KDF is that humans don't do that.

Re: My USB Drive Has a Hidden Encrypted Vault

#50

Post by gruez »

>Many places don’t respect privacy laws, in certain situations you may be forced to unencrypt your media, or worse, assumed to be guilty. A Veracrypt hidden volume is useful in the former situation, but not the latter.

> ...

>Due to AI demand the cost of eMMC memory is unusually high, so I chose to go with an SD card for memory. Someone will find your SD card if they tear it apart, but of course everything is encrypted.

So which one is it? It sounds like this is trading off between "having veracrypt installed on your computer" vs "having a custom usb drive". In other words, hiding something in software vs hardware. I'm not really convinced hardware is better. The hardware device is going to get discovered if the x-ray it, not least because of the super suspicious embedded sd card reader. Even if we concede that hiding in hardware is better, surely you can just use whatever trick to hide the software (eg. putting in a secret password mounts a second drive with veracrypt)? That way you don't run into the crypto issues that the parent poster mentioned.

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