Ransomware Decryptor
noransom.kaspersky.com
noransom.kaspersky.com
I'm very pleasantly surprised to see our police doing something good! It's the first time I've heard the Dutch digital police actually achieving anything, and that is not exaggerated. Last time we provided an IP address involved in a hack (the IP was from the same town as the company that got hacked, so it wasn't masked), we never heard anything back, even though we know they have the CIOT database with all Dutch IP addresses mapping to names and addresses. But that was 2 years ago and there have been a lot of activities in training policemen for digital investigations.
Although it's not entirely clear what exactly their involvement was, this is nice!
It's just one of those facts of life: nobody really cares, not until they're directly affected by it somehow.
> nobody really cares, not until they're directly affected by it somehow.
He explicitly marked it as such.
> It's just one of those facts of life:
He is right.
People probably want to keep CoinVault around in case the key isn't known and they want to pay the ransom.
[0] https://noransom.kaspersky.com/static/convault-decrypt-manua...
Besides, you can always use Kaspersky's tool with a paid for key.
What does "check payment and receive keys" really do? Does it check the Bitcoin block chain to see if payment has been made, then calculate the decryption key? Is this entirely blockchain-based?
GP is saying that if the [private] key is password protected, it can be brute forced. Surely if a human is able to type in the password to the private key, you can bute force that password relatively easily?
Of course, there are many other factors that can significantly decrease or break the security of AES.
TL;DR xkcd.com/538
"Easily" conceptually, yes, but not computationally.
>What does "check payment and receive keys" really do?
Presumably it asks the server whether the payment was received, and if the answer is yes, the server sends it the key.
Maybe malware operators aren't that experienced, who knows.
There was an early version that would generate the private key locally, which was discovered by Symantec (the original blog post isn't loading, but you can see it at https://archive.is/1AGHG) For an analysis of a more recent version that fixed this see http://www.secureworks.com/cyber-threat-intelligence/threats...
A TorLocker had flaws that allowed 70% of infections to be recovered, see https://securelist.com/blog/research/69481/a-flawed-ransomwa..., although they didn't explain what flaws there were.
So they were able to dump a memory segment into a hex editor, and locate references to RijndaelManaged. So what?
In the screenshot, I still see:
Server.GetKey().Key
Reading between the lines, the police located the server, served a subpoena to the hosting company, and took possession of the server. They then turned it over to Kaspersky who created the site based on the keys on that server.
The screen dumps are just showing how they figured out the decryption routine - the private key alone doesn't do you much good if you don't know the algorithm used.
Then they don't understand backups - what's the use of backups if rm -rf / erases them as well because they're permanently mounted at /srv/backup?
I would format any disk that has had ransomware on it before I did anything else (like plug in the usb drive with my backup). In the meantime use another PC to access the files.
However yes it is probably worth having 2 backups for this reason, just incase you get caught short.
Obtain data? How? :)
>The National High Tech Crime Unit (NHTCU) of the Dutch police recently obtained a database from a CoinVault command-and-control server containing decryption keys, the Dutch police said in a news release. The information obtained from that database allowed Kaspersky to build a decryption tool.
So, is there anything stopping them from setting up new servers with new keys and starting the goose chase all over again?
It helps some people already infected.
Perhaps the ransomware developers don't understand this or thought it was too much work, or perhaps they want to provide a better user experience by sending a unilateral unlock code rather than requiring the victim to send any data to the attacker.
Congratulations to the people behind this collaboration for making progress on helping the victims.
The private-key to generate the session-key has to exist somewhere -- you don't want it anywhere it can be traced back to you, so it would probably be on some automated control server - which tracks the payment addresses and forwards the decryption key on bitcoin payment receipt.
My guess best is that some of the keys got recovered in the C&C Server take-downs. It would be possible to use bitmessage or another non-ip traceable method of communication to pass decryption keys and and keep the structure separate from the C&C servers.
They are. CryptoLocker[1], which CoinVault is loosely based on, used per infection keys, and the warnings on the Kaspersky site make it clear they don't believe they got all the keys, which would mean there's more than a few keys.
[1] http://en.wikipedia.org/wiki/CryptoLocker
> But then considering this is software made by criminals, I would not expect even the most sensible or trivial of features and security precautions would be implemented.
I'd advise against underestimating your enemy in this global age. These aren't petty thieves akin to digital purse snatchers, working haphazardly, but the work of a few motivated individuals, likely with ties to organized crime.
More specifically on the topic of ransomware, have a look at this gem [1], which uses RSA, but the key is 128 ASCII digits. Very similar to the cryptocat disaster. [2]
[1] http://blog.cassidiancybersecurity.com/post/2014/02/Bitcrypt...
https://securelist.com/blog/69595/challenging-coinvault-its-...