Brazil's Mercado Bitcoin pauses withdrawals after a $38m hack
Why it matters
It is the second big exchange break-in within days, and this one wasn't a code bug: someone got the power to sign transfers. If you place client crypto with a platform, ask how it guards its signing keys and who covers losses.
The short version
Mercado Bitcoin, a Brazilian crypto exchange with 4.8 million customers, paused deposits and withdrawals on 2 November after about $38m was drained from its wallets, the company said. Around $11m has been frozen with help from Tether, Circle and others. Chainalysis puts the loss higher, at $49m across 17 blockchains.
Here's what happened. Early on Monday 2 November, Mercado Bitcoin discovered a security incident, and wallets linked to the exchange were drained. It paused deposits and withdrawals while it investigates and works with authorities.
The exchange put the assets involved at about $38m, according to TokenPost. Around $11m has been frozen with help from Tether, Circle, Paxos, BRL1 and Chainalysis, and the company says more may follow. Tether's chief executive, Paolo Ardoino, confirmed about $4.5m of its USDT linked to the theft was frozen, CoinDesk reported.
Chainalysis has a bigger number: $49m taken across 17 blockchains, according to The Defiant.
How did it happen? CoinDesk said the transfers were ordinary transactions, not a flaw in a smart contract (the code that runs on a blockchain). Nobody yet knows how the attacker got the power to sign them. No one has been blamed, and there is no public evidence tying it to the Binance attack.
The exchange, which has 4.8 million customers and has run for more than 13 years, says no customer assets were lost and no data was exposed. It has not set a date to reopen.
Where this comes from
Written with AI from the sources above and checked against them before publishing. Here's how we work. This is news, not financial advice. Spotted a mistake? Tell us.