Mercado Bitcoin Hot-Wallet Theft Reached as Much as $49 Million as Attacks on Exchange Back Offices Continue

Rekt News has published post-mortems on two exchange thefts from the past two weeks. In both, attackers emptied hot wallets through the exchanges' own operational systems rather than through a flaw in smart-contract code.

The more recent theft hit Mercado Bitcoin, which The Block describes as Brazil's largest crypto exchange, on November 2. The exchange put the loss at about $38 million. Analysts put it above $46 million, and Chainalysis estimated about $49 million moved across 17 blockchains. Security firms said the drain used standard transfers rather than a contract exploit, which means the attacker controlled signing authority over the hot wallets. The exchange has not said whether that came from stolen keys or from the systems that authorize withdrawals. A Mercado Bitcoin director called Chainalysis at 2:30 a.m. Eastern time, and the firm contacted law enforcement within 30 minutes. Roughly $10 million to $11 million was frozen with help from Tether and Circle. The exchange reopened in view-only mode on November 9 and says it will cover customer losses from its own reserves. Some analysts suspect a link to an earlier BitMart theft, which nobody has confirmed.

The Binance theft of October 29 is much larger. The FBI attributed the $6.3 billion theft to a North Korean unit it calls TraderTraitor. Cointelegraph describes it as the largest crypto theft on record. North Korea's state news agency called the claim "absurd rhetoric," and President Donald Trump said, "We don't know, we're looking at that." Binance says it has covered about 95% of the affected amount, and the rest consists of less liquid tokens.

The same pattern appears in payment providers that serve crypto brands. In August an outdated Solana card contract run by the provider Rain allowed a signature-verification bypass that gave an attacker administrative control of card-collateral accounts and about $1.1 million. Ron Tarter, chief executive of MNEE App, told crypto.news that card brands hold little control over the upstream services they depend on.