Mercado Bitcoin Halts Withdrawals After Security Incident as Hypernative Flags $40M Outflows

Tether has blacklisted two more of the attacker's addresses, on Ethereum and Tron, freezing the USDT sitting inside them. Mercado Bitcoin (MB) suspended deposits and withdrawals on Monday after more than $40 million left wallets tied to the Brazilian exchange overnight, according to security firm Hypernative. The exchange confirmed the incident in a statement on X, saying it had identified and quickly contained a security incident in one of its systems early that morning. MB said customers suffered no losses and no customer data leaked. “Our teams are mobilized investigating the case, tracking the assets and coordinating measures with the competent authorities,” the company said. Flows Across 10 Chains Hypernative said the transfers ran across at least 10 blockchains, including Bitcoin, Ethereum, Solana and Tron. The first suspicious transfer came at 2:15 UTC. The largest transfers came between 6:19 and 6:53 UTC, when wallets tied to MB sent most of the funds to newly created addresses. Those transfers were ordinary signed transactions, sent as if the source wallets had authorized them. Hypernative said it is not yet clear how the attacker got the power to sign those transactions. ...