# Mercado Bitcoin Suspends Operations Following $40 Million Security Breach Exchange halts withdrawals after unauthorized outflows across ten different blockchain networks were detected. - **Source:** [CryptoPotato](https://brifing.si/source/bd22636b-ec8d-42a8-8cca-1937c50e0f6c) - **Published:** 2026-11-02 - **Topic:** [Finance](https://brifing.si/c/finance) - **Original article:** - **On Brifing:** https://brifing.si/s/f74cb7ae-e04e-46c5-b397-9a57b93b8fc3 ## Immediate Operational Suspension Mercado Bitcoin suspended all deposits and withdrawals on Monday following a security incident. The exchange confirmed the breach early that morning, stating they identified and contained the issue within their systems. Despite the disruption, the company claims no customer data was leaked and no individual user funds were lost during the event. ## Hypernative Identifies Massive Outflows Security firm Hypernative reported that over $40 million left wallets associated with the Brazilian exchange overnight. The suspicious activity spanned at least ten different blockchains, including Bitcoin, Ethereum, Solana, and Tron. These transfers occurred between 2:15 UTC and 6:53 UTC, with the majority of funds moved to newly created destination addresses. ## Unauthorized Transaction Signatures The transfers appeared as ordinary signed transactions, suggesting the attacker possessed the authority to initiate them. Hypernative noted that it remains unclear how the perpetrator gained the power to sign these specific transactions. The firm is currently verifying if all identified source addresses belong exclusively to the Mercado Bitcoin exchange infrastructure. ## Asset Tracking and Freezing Mercado Bitcoin published five destination addresses linked to the incident across various networks. Data from mempool.space shows one significant transfer of 104.4 BTC occurred at 6:41 UTC. Meanwhile, Tether has intervened by blacklisting its USDT contracts on both Ethereum and Tron, effectively freezing over 3.7 million USDT held in attacker-controlled addresses. ## Multi-Chain Attack Mechanics The attacker utilized multiple chains to distribute the stolen assets, complicating recovery efforts. By moving funds across EVM networks, Bitcoin, Solana, Stellar, and Tron, the perpetrator attempted to obscure the trail. Mercado Bitcoin teams are currently coordinating with competent authorities to track these assets and implement necessary measures to secure the platform. ## Context of Recent Thefts This incident follows a massive $6.3 billion loss reported by Binance on October 29. That breach was traced back to a compromised DevOps engineer's laptop, which allowed unauthorized withdrawals. Like Mercado Bitcoin, Binance was forced to halt withdrawals temporarily while they overhauled their internal security protocols to prevent further unauthorized access to hot wallets. ## Comparison of Security Failures While the Binance theft remains the largest on record, the Mercado Bitcoin incident highlights ongoing vulnerabilities in exchange wallet management. Both cases involved attackers bypassing standard withdrawal authorization processes. The industry is now observing how these exchanges manage the recovery of frozen assets and the subsequent restoration of their platform services. ## Future Security Implications The ability of stablecoin issuers like Tether to freeze assets on-chain provides a critical layer of defense against such breaches. Moving forward, exchanges must focus on securing the signing mechanisms that authorize large-scale transfers. The industry will likely see increased scrutiny regarding DevOps security practices and the management of private keys for hot wallets. ## Sources covering this story - https://cryptopotato.com/mercado-bitcoin-halts-withdrawals-after-security-incident-as-hypernative-flags-40m-outflows/ — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._