Harmony to Roll Back Blockchain After Fake ONE Mint Hack, Canceling 109,000 Transactions

Layer-1 blockchain Harmony will roll back its chain to an earlier state to contain the fallout from a hack involving the unauthorized minting of fake ONE tokens.

Cointelegraph reported on August 17 that Harmony told validators it would revert the chain to the block recorded at 11:25 p.m. UTC on August 11. Blocks after that point will be regenerated using a replaced database.

The rollback will cancel 109,126 regular transactions and 315 staking transactions. Harmony said selectively restoring transactions would be unsafe because balances, contract states and nonces would differ on the replacement chain.

The incident began when an attacker minted Harmony's native token, ONE, without authorization and sent it to exchanges. Harmony said its investigation traced most of the fake ONE tokens to specific wallets or service boundaries and that it is coordinating with exchanges, bridges and law enforcement. According to CoinGecko, ONE's current market capitalization is about $10.8 million.

Harmony's decision marks the second known case after Ravencoin sought to reverse blockchain transactions that had already been finalized following a hack. Ravencoin previously pursued a chain reorganization to roll back as much as three days of blocks after a vulnerability in its consensus algorithm was exploited.