Key conclusions
- The attacker minted approximately 4 billion ONE tokens on the Harmony network, or more than a quarter of the entire supply. The standard supply readout that exchanges and apps use showed the old number for this time.
- Before anyone saw inflation, about 2.8 billion coins were already sitting on exchanges. ONE fell to a historic low of $0.0005735.
- Harmony is considering reverting the chain to its pre-attack state. This would also erase the legal transactions of ordinary users, and they will not recover the coins on exchanges anyway.
- In the same week, Ravencoin goes through the same thing. The two mines with the majority of capacity are rewriting the chain there from the August 7 block, risking invalidation of three days of transactions.
Late Tuesday evening, on-chain analyst Juiceberg noticed that less than 4 billion ONE tokens had been added to the Harmony network, which no one should be able to create. With approximately 15 billion coins in legal circulation, this meant a sudden increase in supply by more than a quarter. The equivalent would be a central bank printing a quarter of a country’s currency supply in one transaction, without announcement. Harmony confirmed the exploit three hours later and admitted that it was considering rolling back the entire chain.
A reprint that was not visible in the data
The most interesting thing here is not the gap itself, but what covered it. Interface totalSupplywhich is a standard query with which the exchange or wallet checks how many coins exist, did not show new tokens in real time. The market defenses looked at the exact spot where the attack was supposed to be visible and saw nothing.
Harmony exploited as on-chain data reveals unauthorized 4B ONE mint (26% of supply) via empty blocks, with 2.8B quickly funneled to exchanges as price crashed while totalSupply endpoint hides the inflation $ONE
The result was a time advantage. According to Juiceberg’s analysis, approximately 2.8 billion freshly minted coins hit exchanges almost immediately, before the team could request a freeze of funds. Less than 3 percent of what was printed was left for sale on the chain.
On-chain verifiability is a real advantage of Bitcoin and its derivative networks, but you validate it through a specific interface. If that interface lies, you’re left believing the team’s message, which is exactly what all this technology was supposed to move away from.
Third such incident in four years
Harmony released an emergency patch for validators, paused Horizon Bridge and published four wallet addresses asking exchanges to block it. No exchange has publicly confirmed that it has done so. The ONE price dropped to a historic low – the price reduction reached approximately 40 percent within 24 hours. The capitalization of the project, which was valued at over USD 4 billion in 2021, is today approximately USD 11.5 million.
This is the network’s third major failure in four years. In 2022, the Horizon Bridge lost $99.7 million and the FBI attributed the attack to the North Korean group Lazarus. In December 2023, an error in staking logic generated 146 million excess coins. Each time, the same recovery scenario is repeated: a request to the exchanges to freeze funds, and then a message about conclusions for the future.
Can a confirmed transaction be reversed?
This is the whole truth about blockchain immutability in one paragraph. This is not a mathematical property, just a contract of most computing power. With Bitcoin, rewriting three days of history would cost astronomical money today, and that’s why no one does it. With a network worth several million USD, it is enough for two mines to reach an agreement.
What does this mean for you
If you keep anything on a small network, your risk is not just that your wallet gets hacked. It is also the decision of several entities that the transaction you saw as confirmed did not take place. When such a situation begins, exchanges immediately stop deposits and withdrawals of the coin in question, just as Upbit did with Ravencoin. Your funds don’t disappear, but you can’t touch them for a few days.
If you plan to transfer some funds in August, OKX pays an additional 8 percent on the deposit by the end of the month – the maximum reward is EUR 5,000. This is a one-time USDC reward spread over 26 installments over a year. Best of all, these funds are not frozen, you can put them into OKX Earn or X Drops Club, and additionally earn interest – you can also trade these assets on the stock exchange. You just need to remember to first click the button and join the promotion, and only then make the transfer.
There are approximately 115 million reprinted coins left on the Harmony chain. The remaining 2.8 billion is in exchange accounts, which will not be reached by any rollback.
