KiloEx released a summary of the hacker incident: a bug in the TrustedForwarder contract in the smart contracts led to this attack.

According to Deep Tide TechFlow news, on April 21, KiloEx released a root cause analysis and post-incident summary of the hacking event. The incident was caused by its smart contracts, where the TrustedForwarder contract inherited from OpenZeppelin’s MinimalForwarderUpgradeable but did not override the execute method, resulting in the function being callable by anyone.

The attack occurred from April 14, 18:52 to 19:40 (UTC), with the Hacker implementing the attack by deploying attack contracts on multiple chains including opBNB, Base, BSC, Taiko, B2, and Manta. After negotiation, the Hacker agreed to retain 10% of the bounty and has returned all stolen assets (including USDT, USDC, ETH, BNB, WBTC, and DAI) to the multi-signature wallet designated by KiloEx.