Harmony confirms exploit involving unauthorized minting of 4 billion ONE tokens

Layer 1 blockchain platform Harmony confirmed on Wednesday that it had been exploited, following a report of an unauthorized minting of its ONE cryptocurrency.

Earlier in the day, an X user named Juiceberg reported that an attacker had minted 4 billion ONE (ONE) tokens by using empty blocks. The token price subsequently plunged, while the totalSupply endpoint did not immediately reflect the increase in supply, according to the X user.

"The attacker has roughly 115M ONE left to sell onchain — about 2.9% of the ~4B they minted," Juiceberg wrote. "The overwhelming majority (~97%) is already on exchanges and has either been sold or is sitting in deposit wallets ready to sell."

ONE token is down 34% in the past 24 hours, trading at around $0.0008. This puts the stolen amount at a current value of roughly $3.2 million.

Harmony directly addressed Juiceberg's post in its X statement, confirming the exploit and saying it is working with its team and relevant exchanges to stop and freeze the funds. It added that it is developing a patch and evaluating rollback options.

The incident remains under investigation, and Harmony has not yet disclosed the technical root cause of the exploit. The Block has reached out to Harmony for further information.

Second major exploit

This is not the first major security incident involving Harmony. 

In June 2022, the project's Horizon cross-chain bridge was exploited. Attackers stole crypto assets valued at nearly $100 million, including Ethereum and various stablecoins. Security experts linked the breach to a compromise of the bridge's multi-signature wallet.

In January 2023, the FBI attributed the attack to the North Korean state-backed hacker organizations, the Lazarus Group and APT 38.

Harmony launched its mainnet in 2019 as a proof-of-stake blockchain presenting itself as a faster and cheaper Ethereum alternative. It uses ONE as its native token for transaction fees, staking, and governance.

This is a developing story.