Earlier this year, the Ronin bridge was hacked and this saw cybercriminals steal almost $625 million worth of cryptocurrencies from the protocol in question.

It is believed that the North Korean hacking group Lazarus was behind the attack on the protocol. Even though their identity has been exposed, they have continued to conduct transactions anonymously.

How? The hacking group has managed to accomplish this goal through the use of Bitcoin privacy tools that have helped them in maintaining their anonymity.

The stolen funds

Working for SlowMist, an on-chain investigator by the name of BliteZero disclosed the activities of the attackers of the Ronin bridge protocol.

The company disclosed the route that was taken by the fund stolen in the attack from the day the incident occurred.

Most of the funds that were stolen were first converted into Ether and then the Tornado Cash mixer was used for laundering the funds.

Later, the funds had been bridged to the Bitcoin network and the Ren protocol was used for converting them into BTC.

As mentioned earlier, it is believed that the notorious Lazarus hacking group from North Korea was behind the attack.

When they first carried out the exploit, they had transferred part of the funds into centralized exchanges. About 6,249 ETH had been transferred to FTX and Huobi.

Privacy tools

Once they had made the transfer of funds to these exchanges, the hackers then decided to convert them into BTC.

They then took advantage of the Bitcoin privacy tool called Blender for transferring about 439 BTC, which was valued at $20.5 million,

The tool was later sanctioned by the US Treasury Department back in early May. According to analysts, all the funds that were withdrawn by hackers had been deposited into Blender and taken off exchanges.

The majority of the funds that the hackers stole from the Ronin bridge, which were around 175,000 ETH, had been transferred between April 4th and May 19th to the Tornado mixer.

About 113,000 ETH was converted into renBTC through decentralized exchanges like 1inch and Uniswap. The hackers then used the Ren bridge for transferring assets to the Bitcoin network from the Ethereum blockchain.

Decentralized protocols and exchanges were later used for transferring about 6,631 BTC. Another bitcoin privacy tool called ChipMixer was used by the Ronin network for withdrawing 2,817 BTC.

The exploit

The Ronin network’s exploit was one of the most devastating ones to date for the crypto sector. The decentralized finance (DeFi) space has seen one hack after the other this year.

This has highlighted a weakness in the security policies of different protocols, indicating that they need to work on it to prevent future exploits.

The Ronin bridge is used by the renowned play-to-earn game called Axie Infinity and the platform’s progress was severely affected.

A number of crypto companies, such as Binance, made donations for assisting Sky Mavis after the attack, which is the team running Ronin bridge.

Moreover, Tornado Cash was also sanctioned by the US Treasury because of its use in money laundering activities.