A white hat hacker helped recover $2 million worth of ETH locked in an ICO contract since 2016.

On June 1st, according to The Block, a developer known by the pseudonym Florent used white-hat hacking techniques to help rescue approximately 1003 ETH (worth about $2 million) that had been locked in the 2016 HongCoin ICO contract for nine years. The ICO was supposed to automatically refund investors as it failed to meet its funding target, but a coding error caused the funds to be locked. Due to the contract using an older version of the Solidity language, it lacked overflow protection mechanisms. Florent discovered that by calling the team's admin function and inputting specific values, the holder's balance could be reset to 1, thereby releasing the ETH through the refund check. This admin function was limited by HongCoin's multi-signature address. Florent contacted the team, and after verifying the process on the testnet, the team signed the unlocking transactions themselves. The entire process took about a week, during which the team signed 41 transactions covering approximately 1000 ETH. Two investors have currently claimed 96.5 ETH and voluntarily paid Florent a white-hat bounty. Florent stated that his motivation was curiosity and a desire to understand how old contracts worked.