Harmony’s ONE falls 26% after attacker allegedly mints 4 billion tokens

Harmony’s ONE falls 26% after attacker allegedly mints 4 billion tokens

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Harmony’s ONE dives 26% after an attack appears to mint tokens equal to quarter of supply

Harmony said in Asian morning hours it is working with exchanges to freeze funds and preparing a software fix.

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Shaurya Malwa

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Harmony’s ONE falls 26% after attacker allegedly mints 4 billion tokens. (Unsplash)

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Harmony’s ONE token plunged about 26% after an apparent exploit created roughly 4 billion new tokens, increasing the supply by more than a quarter.

The Harmony team confirmed the incident, said it is working with exchanges to freeze funds, and is preparing a software patch and possible rollback of the blockchain.

The episode follows earlier security and token-creation issues on Harmony, including a 2022 $100 million bridge hack and a 2023 bug that improperly minted about 146.3 million ONE.

Harmony’s ONE token fell about 26% in Asian morning hours Wednesday after an

apparent exploit

created roughly 4 billion new tokens, an amount equal to more than a quarter of the token’s existing supply.

Harmony confirmed the attack in an X post and said it is working with exchanges to freeze the funds and preparing a software fix.

“We are working on a patch and rollback options,” Harmony said, adding that it would provide another update when more information is available.

Harmony is a layer 1 blockchain network for DeFi protocols and marketplaces. Its native token, ONE, is used to pay for transactions and help secure the chain. Roughly 15 billion ONE existed before the incident, meaning another 4 billion represents a sudden increase of about 26% against that supply.

A potential rollback by Harmony would mean returning the network to a state before the exploit and continuing from that point, effectively removing transactions that occurred afterward from the blockchain’s accepted history. Imagine being allowed to undo a chess move that led to checkmate and restart from an earlier, safer position on the board.

That can prevent an attacker from keeping newly created tokens still on the network, but becomes harder once funds have reached exchanges or moved onto other systems. Many in the industry, however, view a rollback as antithetical to blockchain’s core principle of immutability.

The apparent exploit comes a day after Ravencoin, another smaller blockchain built from Bitcoin’s code,

faced its own possible rollback

after parts of its network accepted invalid blocks.

In that case, miners moved to rebuild the chain from before the flaw, putting several days of transactions at risk of reversal. Ravencoin is separate from Harmony, but the two incidents show the trade-off involved in a rollback – that undoing an attack can also undo legitimate transactions made after it.

Not the first hit

Harmony has dealt with unauthorized creation of ONE before.

In December 2023

, a bug in its staking system caused about 146.3 million ONE to be created when tokens that should have stopped receiving payouts continued to receive them. Harmony said at the time that 74 addresses were involved, with one receiving 51.2 million ONE, and that about 16.4 million was subsequently moved to an exchange.

The network responded to that incident with an emergency software update and blacklisted addresses holding the improperly created tokens.

Harmony was also hit by one of crypto’s

biggest bridge attacks in 2022

, when about $100 million was stolen from its Horizon bridge after attackers compromised private keys controlling it. The FBI later attributed that theft to North Korea’s Lazarus Group.

Wednesday’s incident appears different because the reported damage involves the creation of ONE on Harmony itself rather than assets being stolen from a bridge.

Harmony has not yet explained the vulnerability, how the 4 billion figure was calculated or how far back any proposed rollback would go.

(This story is developing.)

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