Mercado Bitcoin Suspends Transfers After Security Incident

Brazilian cryptocurrency exchange Mercado Bitcoin suspended deposits and withdrawals on November 2 after identifying a security incident in one of its systems. The company said it had contained the incident and that the pause was a precaution while staff investigated and tracked assets. Mercado Bitcoin said customers suffered no losses and no customer data was leaked. It also said it was coordinating with relevant authorities. Those assurances are the exchange’s statements; the company has not confirmed a final loss figure or explained how the incident occurred. Blockchain security firm Hypernative preliminarily identified more than $40 million in suspicious transfers across at least 10 networks from wallets it attributed to Mercado Bitcoin. Hypernative said the estimate remains subject to confirmation that the source wallets belonged to the exchange. Suspicious transfers do not establish that the full amount was stolen or that customer assets were involved. Researchers described the activity as ordinary blockchain transactions rather than a confirmed smart-contract exploit. Hypernative reported that the transfers appeared to be signed as if authorized by the source wallets,...