Law enforcement officers from Switzerland and Germany have taken down the Cryptomixer cryptocurrency-mixing service, believed to have helped cybercriminals launder stolen funds.
The joint action was part of “Operation Olympia,” and it took place between November 24 and November 28 in Zurich, Switzerland.
Authorities, supported by Europol and Eurojust, seized three servers and the clear web and Tor .onion domains, along with €24 million in Bitcoin.
“Cryptomixer was a hybrid mixing service accessible via both the clear web and the dark web. It facilitated the obfuscation of criminal funds for ransomware groups, underground economy forums and dark web markets,” Europol said.
“Its software blocked the traceability of funds on the blockchain, making it the platform of choice for cybercriminals seeking to launder illegal proceeds from a variety of criminal activities, such as drug trafficking, weapons trafficking, ransomware attacks, and payment card fraud.”
Europol supported a similar action in March 2023 targeting the ChipMixer cryptocurrency mixing service (one of the largest dark web crypto mixers at the time), when law enforcement in Germany (BKA) and the United States (FBI) seized four servers, 7 TB of data, and $46.5 million in Bitcoin.
Crypto mixers (or tumblers) add users’ cryptocurrency to a single, large pool and distribute it across many new wallet addresses, making it much more difficult to trace the funds back to criminal activities and, in many cases, effectively hiding the source of illegally obtained cryptocurrency.
Crypto mixers also take a commission on all laundered crypto deposited before sending it to another wallet address owned by their “customers.”
Just like run-of-the-mill money laundering operations, mixing services like Cryptomixer provide clients with anonymity and are often used by criminals before converting stolen assets into fiat currency or other cryptocurrencies using bank accounts and cash machines.
Although there may be legitimate use cases for such services, they are mainly used by cybercrime gangs to evade identification and prosecution.
Earlier this month, the founders of the Samourai Wallet (Samourai) crypto mixer were also sent to prison in the United States for helping criminals launder over $237 million, while a Chinese woman known as the “Bitcoin Queen” was sentenced in the UK to nearly 12 years for laundering Bitcoin from a £5.5 billion ($7.3 billion) cryptocurrency investment scheme.
In January, U.S. prosecutors also indicted three operators of the Blender.io and Sinbad.io crypto-mixing services, which ransomware gangs and North Korean hackers used to launder stolen cryptocurrency and ransom payments.