Wallets Linked to Mercado Bitcoin Continue Transferring Assets Following $46M Security Breach
Following a cyberattack, Brazilian cryptocurrency platform Mercado Bitcoin halted deposit and withdrawal services while maintaining that user assets and personal information remained secure.
One of the leading cryptocurrency exchanges in Brazil, Mercado Bitcoin, has acknowledged a cybersecurity breach that resulted in the loss of more than $46 million in digital assets from its wallets this Monday. Although the platform announced that it had halted all deposit and withdrawal operations, blockchain addresses linked to the security incident kept receiving transfers for several hours following the initial statement.
According to cybersecurity experts, the breach was executed using conventional transfer methods rather than exploiting vulnerabilities in smart contracts.
Dickson Wu, who serves as a senior security engineer at Certik, released a preliminary analysis of the attack, noting that the perpetrators "picked at eight small chains for four hours," which included networks like Base, Optimism and Arbitrum. Following this initial phase, the assault targeted the exchange's primary hot wallet infrastructure before executing minimal Ether (ETH) transactions from a total of 27,160 separate addresses.
"So whoever did this can also move money out of MB's customer deposit addresses," he wrote.
Funds move despite suspension
Several hours following Mercado Bitcoin's public announcement regarding the temporary halt of deposit and withdrawal functionality, cryptocurrency assets kept flowing out of blockchain addresses connected to the security compromise, subsequently followed by thousands of minor ETH transactions being consolidated into one single address.
When contacted by Cointelegraph, a representative from Mercado Bitcoin confirmed that no customer losses had occurred and that no sensitive data had been compromised, though the company declined to provide additional commentary regarding the ongoing transfers. Any potential data breach would also obligate the company to notify Brazil's data protection regulatory authority.
At this time, no organized cybercrime group has claimed responsibility for the attack, and investigations are still ongoing.
Among the stolen cryptocurrency, as of 16:42 UTC roughly $6.2 million in assets had been immobilized by Tether and Circle, both prominent stablecoin issuers. Approximately $20 million had been moved into freshly generated wallet addresses, while more than $20 million continued to sit in related addresses that Mercado Bitcoin had identified, which included the full amount of 106 BTC.
Mercado Bitcoin joins breach list
As of July, Mercado Bitcoin's user base stood at 4.5 million, which coincided with the announcement that Tether, a major stablecoin issuer, had made a $20 million investment to facilitate the platform's growth in areas such as tokenization, payments and credit services. In a related development, Orionx, another Latin American exchange that received backing from Tether and operates in Chile, revealed its shutdown in September following a forensic investigation that discovered more than $7 million worth of customer holdings had been moved to wallets beyond its operational control.
This security breach occurs just days following Binance's disclosure of a massive $6.3 billion cyberattack that targeted its hot wallet infrastructure on Thursday. The global exchange also suspended its deposit and withdrawal services and made a commitment to reimburse all customer losses. By Sunday, Binance had started the process of restoring withdrawal capabilities, announcing that it had successfully recovered 95% of the compromised funds.