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FIGR_HELOC $1.07 Hacks & Security · Explained
Mercado Bitcoin freezes deposits and withdrawals after security incident
Brazilian exchange Mercado Bitcoin says clients lost nothing, Hypernative estimates more than $40 million left wallets it links to the platform.
Key takeaways
- Services paused. Deposits and withdrawals were suspended on Nov. 2, with no restart timetable announced.
- Disputed figure. Hypernative estimates more than $40 million was drained; Mercado Bitcoin has not confirmed that number.
- No customer loss claim. The exchange says clients lost nothing and no data leaked, without disclosing which system was affected.
What happened
Mercado Bitcoin, a Brazilian cryptocurrency exchange, suspended deposits and withdrawals on Monday, Nov. 2, after detecting a security incident in one of its systems. In a statement on X at 12:56 UTC, the exchange said it had identified and contained the incident overnight, that clients had suffered no losses and that no data had leaked. It said its teams were investigating, tracing assets and coordinating with authorities. Crypto.news reported that the suspension was precautionary and that no restart date had been announced.
About 90 minutes later, Mercado Bitcoin published destination addresses tied to movements in the incident on EVM networks, Bitcoin, Solana, Stellar and Tron, saying they were shared only so they could be identified and tracked. Hypernative, a blockchain security firm, estimated that more than $40 million had been drained from wallets it attributes to the exchange, Unchained reported. Mercado Bitcoin has not confirmed that estimate, has not called the event a hack and has not said whose funds moved.
Crypto.news reported that the exchange did not disclose which system was affected or whether any assets were stolen, and did not identify an affected cryptocurrency, network or wallet address in its initial statement. The company said it would keep clients informed through official channels while working to restore operations safely.
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Why it matters
The immediate effect for users is that they cannot move crypto into or out of the platform, and the exchange has not said when that will change. Crypto.news noted that Mercado Bitcoin also did not specify whether other functions, including trading, were affected. The case puts attention on disclosure: the exchange's assurance that customers lost nothing and Hypernative's estimate of more than $40 million in outflows address different questions, and Mercado Bitcoin has not publicly reconciled them.
What the data shows
Hypernative's alert, shared by Opsek founder Pablo Sabbatella, described the outflows as 'plain transfers, not a smart contract exploit' and said it was unclear how the attacker obtained signing access. The firm counted about 2,852 ETH, 106 BTC, 10,700 SOL and 6.7 million XLM, plus more than 200 other tokens, in fresh addresses on at least 10 chains. It named Ethereum, Bitcoin, Solana, Tron, Polygon, Arbitrum, Avalanche, BNB Chain and Stellar.
Hypernative said most of the money moved in a 34-minute window from 06:19 to 06:53 UTC, while sweeps of the exchange's bitcoin deposit addresses began earlier, at 02:15 UTC. Unchained's review of the Bitcoin address named by Mercado Bitcoin found it had received about 106.07 BTC across seven transactions by 14:58 UTC, including 104.43 BTC in a single transfer timestamped 06:41 UTC; none had left the address at the time. Mercado Bitcoin has not confirmed Hypernative's figures.
Background
The incident came four days after Binance suffered a major breach on Oct. 29. Crypto.news reported that about $6.3 billion in assets were affected and that Binance temporarily suspended withdrawals after attackers compromised an engineer's laptop to reach internal withdrawal infrastructure. Binance said wallet private keys were not exposed. By Oct. 30, about $3 billion of affected assets had been frozen on-chain, and Binance pledged to cover customer losses with its Secure Asset Fund for Users and corporate funds. By Nov. 1, it said it had replaced about 95% of stolen assets and begun restoring withdrawals in phases.
The same week, Aave restricted some markets after a wallet linked to the Binance attacker deposited 60 million USDT and borrowed 19,762 WETH, and BTCPay Server warned of unauthorized hot-wallet withdrawals from installations running version 2.4.1 or earlier, Crypto.news reported.
What is still unclear
Mercado Bitcoin has not identified the affected system, said whether unauthorized transfers occurred, given a loss figure or explained how the incident was contained. It has not said when deposits and withdrawals will resume, whether trading was affected, which authorities it is working with or whether any funds have been frozen. Hypernative said it was unclear how the attacker obtained signing access. Neither the exchange nor Hypernative has tied the incident to the Binance breach.
What to watch
The next signals will be Mercado Bitcoin's updates on restoring deposits and withdrawals, any confirmation or denial of Hypernative's figures, and details from the asset-tracing effort. Authorities could add another source of information, but the exchange has not named the agencies.
Questions readers ask
Did Mercado Bitcoin customers lose funds?
The exchange says no client losses occurred and no data leaked. It has not given a loss figure, and Hypernative's estimate of more than $40 million in outflows has not been confirmed by the company.
When will withdrawals resume?
Mercado Bitcoin has not announced a timetable. It said it is working to restore operations safely and will update clients through official channels.
Was the incident a hack?
Mercado Bitcoin has not called it a hack. Hypernative described the outflows as plain transfers rather than a smart contract exploit and said how signing access was obtained remains unclear.
Sources · 9 publishers
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Brazil’s Mercado Bitcoin reports security incident, freezes withdrawals -
Mercado Bitcoin Halts Withdrawals Over Security Incident as Hypernative Flags $40 Million Drain -
Brazil’s largest crypto exchange Mercado Bitcoin halts withdrawals after reported $40M hack -
Brazil’s Mercado Bitcoin Freezes Deposits and Withdrawals Due to Ongoing Security Incident, Losses Estimated Near $40 Million -
6.7 Million Stellar (XLM) Stolen in Massive $40 Million Mercado Bitcoin Breach -
Brazil’s Mercado Bitcoin Halts Withdrawals After Estimated $46M Stolen -
Brazil's Largest Exchange Mercado Bitcoin Halts Withdrawals After $40 Million Hack -
Mercado Bitcoin Halts Withdrawals After Security Incident as Hypernative Flags $40M Outflows -
Mercado Bitcoin, Brazil’s largest crypto exchange, hit by $46 million security breach
