Briefing
The Force Bridge cross-chain protocol suffered a critical exploit in June 2025, resulting in the unauthorized withdrawal of over $3 million in crypto assets. The primary consequence was an immediate suspension of bridge services and a loss of user-deposited liquidity across multiple token types. Forensic analysis confirms the attacker successfully siphoned a basket of stablecoins and wrapped assets, including USDT, ETH, and WBTC, which were subsequently routed through a mixing service. The total loss exceeded $3 million before the bridge was paused.
Context
Cross-chain bridges are inherently high-risk components within the DeFi architecture, frequently targeted due to their complex, multi-contract logic and high-value custody. This incident follows a prevailing trend where vulnerabilities in bridge design, often involving inadequate key management or smart contract flaws, expose a massive attack surface. The risk was known → bridge exploits represent nearly 40% of all Web3 value hacked, signaling a persistent, systemic fragility in interoperability solutions.
Analysis
The attack vector leveraged a core vulnerability in the bridge’s design or implementation logic. The attacker successfully initiated unauthorized withdrawal requests, effectively bypassing the protocol’s verification or authorization checks. This flaw allowed the siphoning of locked assets across various chains, which were then converted to ETH.
The use of self-destructing helper contracts and immediate funneling of the stolen funds through Tornado Cash served to mask the trail and complicate post-mortem analysis. The root cause is attributed to major vulnerabilities in the bridge’s design and implementation.
Parameters
- Total Loss → Over $3 Million. The aggregate value of siphoned tokens (USDT, ETH, USDC, DAI, WBTC).
- Vulnerability Class → Smart Contract Flaw. A design or logic error in the cross-chain asset transfer mechanism.
- Mitigation Action → Bridge Service Paused. Immediate action taken by the Nervos Network contributor to halt further asset drain.
- Laundering Vector → Tornado Cash. The crypto mixer used to obscure the transaction history of the stolen funds.
Outlook
Immediate mitigation requires all users to cease interaction with the affected bridge and monitor official channels for recovery updates. This exploit will reinforce the demand for formally verified bridge designs and a shift away from centralized control points. The systemic risk of bridge-related contagion remains high, necessitating that all interconnected protocols review their exposure to similar cross-chain asset flows and implement strict, real-time rate-limiting controls.
Verdict
The Force Bridge exploit decisively demonstrates that the security of decentralized finance remains critically dependent on the integrity of complex, high-value cross-chain interoperability mechanisms.
