Validator Keys Hijacked, $2.4M Stolen in Shibarium Bridge Heist

The Shibarium Bridge, a critical component of the Shiba Inu (SHIB) ecosystem linking its Layer 2 network to Ethereum (ETH), fell victim to a sophisticated flash loan attack on September 13, 2025, resulting in the loss of approximately $2.4 million in ETH, SHIB, and KNINE tokens. The attack exploited vulnerabilities in the bridge’s governance structure, enabling the attacker to manipulate the system by gaining control of 10 out of 12 validator keys.

The breach was executed through a flash loan that allowed the attacker to borrow 4.6 million BONE tokens, Shibarium’s governance token. With this control, they drained 224.57 ETH and 92.6 billion SHIB from the bridge and also stole KNINE tokens worth around $700,000 from K9 Finance. The attacker’s wallet was subsequently blacklisted by K9 Finance’s DAO, preventing the liquidation of the stolen KNINE tokens.

In response, Shiba Inu developers swiftly suspended staking and unstaking functions on the network, effectively freezing the attacker’s borrowed BONE tokens. They also transferred stake manager funds into a hardware wallet controlled by a 6-out-of-9 multisig team to mitigate further risks. The team engaged cybersecurity firms Hexens, Seal 911, and PeckShield to investigate the breach and identify its origin.

Developer Kaal Dhairya described the attack as “sophisticated,” noting it may have been planned for months. The source of the vulnerability remains under investigation, with no definitive conclusions on whether it originated from a server or a developer machine. The team is currently in “damage control mode,” prioritizing the security of community assets and the restoration of key functions once the validator control is confirmed to be secure.

The incident had immediate effects on the market. BONE’s price surged from $0.165 to $0.294 within an hour before settling at around $0.202. SHIB, in contrast, rose 4.5% over 24 hours, reflecting a mixed investor response. The Shiba Inu team has indicated that if the stolen funds are returned, they may consider offering a bounty as an incentive.

This attack comes at a vulnerable time for the Shibarium ecosystem, which had previously faced a nearly 99% drop in August. The recent breach has further raised concerns about the network’s stability and security, despite ongoing recovery efforts. The incident underscores the broader challenges faced by DeFi platforms, particularly cross-chain bridges, which remain attractive targets due to their role in facilitating asset transfers across multiple blockchains.

Security experts have emphasized the need for enhanced auditing practices and robust code reviews in DeFi platforms to prevent such attacks. The decentralized nature of these systems, while offering benefits like efficiency and lower transaction costs, also introduces unique risks. The Shibarium bridge attack highlights the urgency for improved security measures and the importance of continuous monitoring and proactive defense strategies.

The Shiba Inu development team has committed to strengthening the security of the Shibarium bridge and the wider ecosystem. They are working with security firms to conduct a comprehensive audit and implement necessary upgrades. The incident serves as a stark reminder of the need for vigilance and innovation in securing DeFi infrastructure as the industry continues to evolve.