Customer funds appear to be unaffected by the Mercado Bitcoin incident, but a second crypto hack in recent days is drawing attention to the industry.
Mercado Bitcoin has suffered a security breach, with approximately $49m in digital assets stolen across multiple blockchains.
The Brazilian cryptocurrency exchange became aware of the attack on 2 November and responded by suspending deposits and withdrawals while it investigated and attempted to limit further damage.
The exchange said hackers targeted hot wallets, which are crypto wallets that maintain a connection to the internet.
Blockchain intelligence firm Chainalysis, which provides services to Mercado Bitcoin, said the attacker moved funds across 17 blockchains, with Bitcoin and Ethereum accounting for the largest portions of the theft. Smaller amounts were also taken from networks including Base, Tron and Polygon.
Mercado Bitcoin said it identified and contained the incident, adding that customer funds were unaffected and no personal data was compromised. It described the suspension of deposits and withdrawals as a precautionary measure.
Neither the exchange nor Chainalysis has publicly confirmed the value of the losses. However, Mercado Bitcoin said it will replace lost funds using its own reserves.
Chainalysis shares details on moments after attack
Chainalysis said it was alerted to the breach in the early hours of the incident and immediately assembled an international investigation team.
The company said it had helped freeze nearly $10m in stolen cryptocurrency by working with the exchange, law enforcement agencies and several digital asset firms.
Its response focused on identifying the stolen assets, tracing their movements and finding opportunities to prevent the attacker from moving or converting funds out of reach.
“The first few hours of any hack are the most important for investigators. In that window of opportunity they can help freeze some assets, like centrally-issued stablecoins, before the attackers are able to convert them into harder-to-disrupt cryptocurrencies, like BTC and ETH,” said Chainalysis.
It contacted several firms, including Paxos, Anchorage Digital, Ripple, Circle and Tether, to share intelligence and coordinate potential freezes.
One example involved stolen Tether’s US dollar-pegged stablecoin USDT, which investigators traced to addresses where the funds could be frozen. Chainalysis said its cooperation with Tether and law enforcement enabled the stablecoin issuer to freeze more than $9m in stolen assets.
The investigation is still ongoing, with the firm monitoring the remaining funds and identifying further opportunities to intervene.
Another major crypto hack in the space of days
This week has put cybersecurity in the spotlight, especially around cryptocurrency. Mercado’s hack comes days after Binance suffered what has been described as the largest cryptocurrency theft on record, with losses estimated at approximately $6.36bn across ten blockchains.
Blockchain intelligence firm TRM Labs attributed the attack to North Korea’s TraderTraitor hacking unit, which the FBI has linked to previous thefts.
Binance’s initial investigation noted a compromised laptop belonging to a DevOps engineer, which allegedly allowed an attacker to access a service container and submit unauthorised withdrawal transactions.
The exchange said there was no evidence of private key leaks and pledged to cover all hacking losses, which it isn’t obliged to do.
Tether, Circle, Ripple and World Liberty Financial froze approximately $2.67bn in stablecoins and Arbitrum’s Security Council moved $30m in assets out of the attacker’s control.
With billions of dollars targeted in the Binance breach and tens of millions more taken from Mercado Bitcoin, the latest incidents have drawn attention to exchange security and the industry’s ability to respond.
