Going through their wallets it looks like they've gotten 32 pay outs, some for more than 300 USD. Are there any addresses that they are using outside of the four listed int he article?
It'd be an interesting project to try and track where these funds go and where they came from.
I haven't looked into tumbling recently, whats the volume look like these days? So far the attack has yielded less than 5 btc, I'd guess that amount can be laundered safely. Whats the current limit?
You can use XMR.to, Shapeshift.io, or Changelly.com over TOR to move funds directly into another another blockchain currency. So have fun following things around Bitcoin blockchain like some high tech sleuth, but thats a wild goose chase.
I buy all my cryptocurrencies through those kind of services nowadays, because there's no risk or temptation to keep coins on custodial exchanges, instead of in a private wallet. As well as no worries about withdrawal limits (although shapeshift has fairly low per transaction limits, just make an additional transaction)
For unlinking the transaction, the only currency you want to cross-chain into is Monero. With its Ring Signatures and Stealth Addresses it is a private blockchain by default (in comparison with some other cryptocurrencies that have a secondary optional privacy feature like Zcash/Shadowcash/Dash).
I'm actually surprised that the ransomware isn't taking Monero directly yet as some exchanges have direct Monero/USD markets already.
I can't speak for a current safe limit, but it isn't very hard to transfer funds between various cryptocurrencies. Tumbling is not secure with a large amount of coins. All you have to do is monitor all transactions and figure out what went in and what came back out. If you start splitting things off in small amounts on various blockchains things become much harder to track.
This is assuming the attackers know what they are doing. I would be against that.
A cursory check doesn't bring up any Helix (the largest tumbler out there) stats. I'm not certain they even make that info public. Also I wouldn't know how to measure the level of privacy in this context.
It'd be an interesting project to try and track where these funds go and where they came from.
https://blockchain.info/address/13AM4VW2dhxYgXeQepoHkHSQuy6N... - 11 https://blockchain.info/address/115p7UMMngoj1pMvkpHijcRdfJNX... - 4 https://blockchain.info/address/12t9YDPgwueZ9NyMgw519p7AA8is... - 6 https://blockchain.info/address/1QAc9S5EmycqjzzWDc1yiWzr9jJL... - 11