A Quarter of the Supply, Printed Overnight

Harmony, the layer-1 blockchain behind the ONE token, confirmed on August 12 that an attacker minted roughly 4 billion new ONE tokens without authorization. The unauthorized mint equals about a quarter of the existing supply of around 15 billion tokens, and it sent the coin to the lowest price in its history.

ONE fell as much as 40% during the early Asian trading session and later traded near $0.0008. For a network with a market value of around $4 billion in early 2022, the damage occurred within hours.

How the Attack Unfolded

The first alarm came from on-chain analyst Juiceberg, who posted on X that billions of new ONE tokens had appeared through empty blocks, a method of creating tokens outside the network’s normal rules. Harmony later confirmed the exploit, saying it is working with its team and relevant exchanges to stop and freeze the funds.

According to Juiceberg’s analysis, about 97% of the minted tokens, roughly 3.88 billion ONE, had already reached exchanges, where they were either sold or parked in deposit wallets ready to sell. Only around 115 million ONE remained on-chain by the time the alert spread.

The speed matters. By the time most holders woke up, the bulk of the new supply had already hit the market.

What a Mint Exploit Does to a Coin’s Price

Minting is the process by which a blockchain creates new tokens. Under normal conditions, strict rules written into the network’s code decide how many tokens can exist and when new ones are issued.

When an attacker finds a way to mint tokens outside those rules, the effect is similar to a counterfeiter printing money. Every genuine token becomes a smaller slice of the pie, and traders who spot the extra supply rush to sell before the price falls further.

The distinction matters. In a typical exchange hack, existing coins are stolen and the total supply stays fixed. In a mint exploit, the supply itself is corrupted, which is why the price damage reaches every holder at once rather than only the victims.

That is why ONE crashed so fast. The market was not just reacting to stolen funds. It was repricing the coin’s entire supply, and anyone with ONE sitting in a crypto wallet watched the value of those holdings shrink within hours.

A $3.2 Million Haul From a Billion-Token Attack

The strangest number in the incident is the smallest one. The Block reported that the minted tokens were worth only about $3.2 million at post-crash prices, because dumping 4 billion tokens crushed the very asset the attacker was trying to cash out.

Harmony has published four wallet addresses linked to the exploit and asked exchanges to block and freeze any funds traced to them. The team also paused its token bridge to stop the minted supply from spreading to other networks.

Whether the freezes recover much is an open question. With most of the tokens already sold or sitting on exchanges, the outcome may depend on how quickly trading platforms acted on Harmony’s request.

Harmony’s Third Security Crisis in Four Years

This is not Harmony’s first emergency. In June 2022, attackers stole around $100 million from its Horizon bridge, an attack the FBI later attributed to North Korea’s Lazarus Group, the same group behind the $1.5 billion Bybit hack now being litigated in a US court.

In December 2023, a separate bug improperly created about 146.3 million ONE across 74 addresses. That incident was small enough for the network to absorb. This week’s mint is roughly 27 times larger and strikes at the core of the network’s token issuance rather than at a peripheral bridge.

No attribution has been made for the new exploit, and Harmony has not yet explained how the unauthorized minting was possible.

Could a Rollback Undo the Damage?

Harmony says it is developing a patch and evaluating rollback options, meaning the chain could potentially be rewound to a state before the attack.

A rollback could erase the minted tokens, but it comes at a cost. Blockchains are prized for immutability, the promise that confirmed transactions cannot be undone. Rewinding the ledger may restore the supply, yet it could also unsettle users and businesses that rely on that promise.

There is a practical problem too. Tokens already sold on exchanges were bought by real traders, and deciding whose transactions survive a rollback could prove as contentious as the exploit itself.

Crypto has been here before. Ethereum faced a version of the same dilemma in 2016, when reversing the DAO hack split the network into two chains, a precedent Harmony’s community may now be forced to study.

A Test of Trust for Smaller Blockchains

The episode landed in an already nervous market. Bitcoin held near $64,000 as traders waited on the July US inflation report, and the exploit rattled altcoins across the board.

The deeper lesson is about monetary integrity. A blockchain’s value rests on the guarantee that its supply rules cannot be broken, and Harmony must now prove that guarantee can be restored. For smaller networks running on thinner security budgets, that is the hardest kind of trust to win back, and how Harmony answers will determine whether confidence returns—a story worth following in the latest crypto news over the coming weeks.