Mercado Bitcoin Halts Deposits and Withdrawals After Security Incident

Mercado Bitcoin, Brazil's largest cryptocurrency exchange, suspended deposits and withdrawals on November 2 after a security incident in one of its systems. The exchange said the incident was identified early in the morning and quickly contained. Customers, it says, lost no money and no data leaked. The information comes from Decrypt, citing the exchange's Portuguese-language statement on X.

What is known about the incident

Mercado Bitcoin described the suspension as a preventive protection measure. The exchange has not given a date for resuming operations, but said it will post regular updates on X. It has not disclosed how attackers gained access to the system and has not confirmed any link to other recent incidents.

The exchange also published destination addresses it identified on five networks: EVM-compatible chains, Bitcoin, Solana, Stellar and Tron. It said the addresses were released so others could track the funds on-chain.

Fund movements and USDT freeze

Blockchain security firm Hypernative, in a preliminary analysis, flagged more than $40 million in suspicious transfers that may be linked to the incident. The transfers span at least 10 blockchains, including Bitcoin, Ethereum, Solana and Tron. Mercado Bitcoin has not confirmed that figure.

Tether CEO Paolo Ardoino said on X that the stablecoin issuer has frozen more than 4.5 million USDT connected to the incident. According to Decrypt, USDT is pegged to the dollar, and Tether can blacklist the addresses holding it so the tokens cannot be moved. A freeze, however, does not by itself return the funds to their owner.

Background: the Binance hack

Decrypt notes that days earlier, on October 29, more than $6 billion was drained from Binance. The FBI attributed that theft to North Korea's TraderTraitor group. Binance has since reopened withdrawals and said it replenished about 95% of the affected assets. Mercado Bitcoin has not linked its incident to the Binance hack, and who is behind its attack remains unknown.