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Here the crypto used by the ransomware seems to be thoroughly and systematically broken, so while it's certainly possible that a stronger variant will appear, I
by tux3 11y ago
Here the crypto used by the ransomware seems to be thoroughly and systematically broken, so while it's certainly possible that a stronger variant will appear, I have my doubts on the author's capacity to do much "better" any time soon.
I'm far from being a cryptographer, but at a glance it looks so weak I have to wonder if it's deliberate.
- kobayashi 11y ago>at a glance it looks so weak I have to wonder if it's deliberate. Any suppositions as to why it would be deliberate?
- djsumdog 11y agoMaybe the person who posted the exploit/solution was the person who created the ransomware? That way they get BTC from people who pay and donations from people who wait? /krazyconspiracy :-P
- atemerev 11y agoIf I was an aspiring ransomware writer, I'd extract _a lot_ of useful ideas from this thread. :P
- petetnt 11y agoMaybe not deliberate, but most likely optimizing encrypting speed over stronger encryption. Better for hit and runs I guess.
- tux3 11y agoWell, I can't say that it's deliberate, but it's definitely some "interesting" choices. A reasonable Salsa20/20 implementation on a modest processor encrypts on the order of 400MiB/s [0][1]. So that the author went to the trouble of halving the number of rounds and changing the word-size when there are perfectly good and plenty fast off-the-shelf Salsa implementations strikes me as rather strange. Surely this is not the bottleneck on most employee's machines. And then there's the apparently tiny keyspace used. You could argue that this makes the key more "user-friendly" (!), but just a hex representation of a random 256bit key would seem much more natural, and the poor targets are hardly in a position to complain. [0] https://www.cryptopp.com/benchmarks.html https://www.cryptopp.com/benchmarks.html [1] https://cr.yp.to/snuffle.html https://cr.yp.to/snuffle.html
- contravariant 11y agoMaybe they wanted to keep CPU usage low? Although disk usage would be noticeable as well (usually).
- sleepychu 11y agoActually customer service is very important to these operations. They have to create trust that paying will relieve your machine of their infliction.
- biot 11y agoTo add to the suppositions: perhaps the author was afraid they may get bitten by their own malware and designed in a weakness as a backdoor in case they lost access to the key server and needed to decrypt their own drive.
- kobayashi 11y agoThis is my favourite of all the answers, because it would mean that the dev would have known how incompetent s/he was, and thus made a weak system in order to account for the likelihood of a "self-inflicted wound".
- cubano 11y agoHere's one...maybe the actual developer who was contracted to build the damned thing purposely used weak encryption to try to ameliorate his/her part in making this malware mess.
- pauljohncleary 11y agoThe targets for this malware are laypeople with enough funds to pay the fee but not enough to go after the creators. Hypothetically, if a national government or other agent with sufficiently deep pockets were infected they would first attempt to crack it, failing that they would go after the creators directly- they would not pay the fee. So implementing weak crypto dramatically lowers the risk of prosecution or worse for the attackers.
- rdtsc 11y agoPresumably they have enough financial resources at the moment, they don't have to do it themselves. They can pay someone to do it.
- stcredzero 11y agoMost anyone able to charge market rates might be more motivated to reveal they've been contracted to do this than to actually do that. Someone who has a hard time getting market rates might not be as qualified to fix the software as they think they are.
- rdtsc 11y agoThere are places in the world were good computer / science education doesn't necessarily mean being able to demand "market rates" comparable to the West. I can see some programmer n Russia or Romania being tempted by a side-deal like this. Especially if presented with a Western "market rate".
- Caprinicus 11y agoMany programmers in Russia and some eastern european countries probably wouldn't even see that as a "side deal"
- rdtsc 11y agoI haven't been back there in many years now, and tried to give the benefit of the doubt ;-)
- Godel_unicode 11y agoPeople who are cryptographers have a tough time writing secure implementations the first time around, is it really surprising that amateurs do?