Whitehat Helps Recover $2M in ETH Stuck Since 2016 ICO

First white-hat exploit on Ethereum: I unlocked 1,003.62 Ξ ($2,000,000) trapped in a 2016 ICO smart contract for 9 years.

0xFlorent_ said he found a way for HongCoin’s old contract to recognize blocked investors again and release their refunds. The recovery covered 48 investors, and he pointed to Etherscan records for the contract and unlocked wallet as on-chain proof.

For years, the contract had relied on the wrong number to decide who could get ETH back. His workaround corrected that for each blocked holder, after which HongCoin’s team carried out 41 unlock transactions.

A whitehat like 0xFlorent_ is a security researcher or developer who finds bugs and uses them to protect systems or recover funds, instead of stealing them.

Because smart contracts can keep running long after projects fade, old mistakes can leave money frozen for years. HongCoin’s recovery suggests some of that money could still move, if the original team can be reached and the contract still gives them a way in.

But recoveries like these remain “unique,” and do not necessarily mean large amounts of lost funds could just “routinely be recovered,” Andy Yajin Zhou, associate professor at the Chinese University of Hong Kong and co-founder of on-chain security firm BlockSec, told Decrypt.

“The recovery was possible because the contract happened to contain a vulnerability that allowed a whitehat developer to safely extract and return the funds,” Zhou said. “Unfortunately, we cannot assume that old Ethereum contracts generally have such flaws.”

Locked funds can remain inaccessible because of "lost keys or irreversible contract logic," Zhou noted, while no reliable estimate exists for how much ETH is permanently trapped in old contracts.

Still, the case suggests that some funds written off as "lost" may not be beyond reach, shows that smart contracts aren’t necessarily “dead ends,” Dominick John, analyst at Zeus Research, told Decrypt.

Better security research and blockchain tools could help recover more stranded assets from old on-chain systems, potentially unlocking "dormant value" while exposing “limitations” in earlier smart contract design, he added.