Harmony rolls back network after exploit erasing transactions

The Harmony blockchain network has initiated a full rollback to erase billions of illegally minted ONE tokens, a drastic measure that will discard over 109,000 legitimate transactions in an effort to restore the ledger's integrity. The recovery plan, announced on August 17, reverts the network to its state on August 11, hours before an attacker exploited vulnerabilities to create a massive unauthorized supply of tokens.

The exploit began on August 12 when an attacker leveraged flaws in cross-shard receipt validation and quorum verification code. While initial reports indicated about 4 billion tokens were forged, a detailed technical update revealed the scale was far larger. A single wallet attempted 534 fraudulent transfers of 5 billion ONE each within a 106-second window, with 477 succeeding. This resulted in the unauthorized creation and transfer of 2.385 trillion ONE tokens, which were quickly routed to cryptocurrency exchanges and decentralized finance pools.

The sudden surge in supply triggered an immediate crash in the price of ONE, which fell by more than 30% in the aftermath. Harmony developers deployed an emergency patch to halt further unauthorized minting and...