Force Bridge Exploit Exposes Access Control Failures as $3.9 Million Drained From Nervos Network

Cross-chain bridge infrastructure faces renewed scrutiny after Nervos Network’s Force Bridge suffers a devastating exploit that siphons nearly $3.9 million in digital assets. The incident, unfolding between May 31 and June 1, 2025, underscores persistent vulnerabilities in bridge architectures that continue to plague the decentralized finance ecosystem.

The Exploit Mechanics

According to blockchain security firm Cyvers Alerts, the attacker seized control of Force Bridge’s cross-chain infrastructure through an access control failure. The exploit targeted both the Ethereum and BNB Chain sides of the bridge, draining a combination of major tokens including 60,400 DAI, 539 ETH, 898,300 USDC, 257,800 USDT, and 0.79 WBTC. The total haul reached approximately $3 million from Ethereum and an additional $800,000 from BNB Chain.

Security researchers at Hacken revealed that the attack was not instantaneous. The perpetrator made multiple failed attempts over a six-hour window before successfully breaching the system. A small test transaction at 02:23 UTC netted just $25, serving as a proof-of-concept before the full-scale assault at 07:36 UTC, when 874 BNB worth roughly $572,000 was drained. This extended attack window represents a critical monitoring failure.

Affected Systems

Force Bridge serves as a critical component of Nervos Network’s multi-chain strategy, facilitating asset transfers between Nervos, Ethereum, and Binance Smart Chain. The bridge operates by locking assets on the source chain and issuing matching tokens on Nervos, protected by a multi-signature wallet system managed by Nervos and its partners.

The compromised bridge had already been announced for deprecation, adding another layer to the incident. Deprecated or sunset infrastructure often receives reduced security attention, creating an exploitable window that attackers can identify and target. In this case, the bridge’s pending shutdown status may have contributed to gaps in monitoring and access control maintenance.

The Mitigation Strategy

Magickbase, a Nervos Network community developer, responded by halting all Force Bridge activity immediately upon detecting the irregular transactions. The team issued a public statement acknowledging the abnormal activity and confirming the precautionary shutdown while investigations proceed.

The stolen assets were quickly routed through crypto mixers and anonymous platforms, including Tornado Cash and FixedFloat, in an effort to obscure the transaction trail. Funds were split among newly created wallets and routed through multiple hops before being deposited to these mixing services, complicating recovery efforts.

Lessons Learned

This exploit reinforces several critical security principles for the crypto industry. First, deprecated infrastructure must maintain full security protocols until complete shutdown, not gradually reduce protections. Second, six-hour attack windows with multiple failed attempts should trigger automated alerts and temporary freezes. Third, bridge architectures remain high-value targets requiring continuous auditing and real-time monitoring.

The Force Bridge incident joins a growing list of cross-chain exploits that have collectively cost the industry billions. With Bitcoin trading at approximately $105,652 and Ethereum near $2,536 at the time of the attack, the total crypto market capitalization above $3.4 trillion makes bridge security a systemic concern affecting the entire ecosystem.

User Action Required

Users who previously transacted through Force Bridge should monitor their wallets for any unauthorized activity. Those holding bridged assets on Nervos Network should check official Nervos channels for updates on the investigation and any potential recovery plans. The broader community should evaluate their exposure to cross-chain bridges and consider whether the convenience of interoperability justifies the additional counterparty risk. As bridge exploits continue to accumulate, the industry must prioritize security architecture over feature velocity to protect user funds and maintain trust in decentralized systems.

Disclaimer: This article is for informational purposes only and does not constitute financial or investment advice. Always conduct your own research before making any financial decisions.