The most ridiculous heist in the crypto world? A hacker minted $1 billion worth of DOT tokens but only stole $230k.

Hackers exploited a vulnerability in the Hyperbridge cross-chain bridge to mint 1 billion DOT tokens out of thin air, with a face value of 1.19 billion USD, but due to severe market liquidity shortages, they only cashed out about 237k USD.

Cryptocurrency attack incidents are happening frequently, but cases like this—“taking big risks for small gains”—are quite rare. Earlier today (13th), a hacker exploited a vulnerability in the Hyperbridge cross-chain bridge to mint 1 billion Polkadot (DOT) tokens on Ethereum, with a nominal value of up to 1.19 billion USD. However, when attempting to sell these tokens, they only received about 23,700 USD in ETH due to severe liquidity shortages.

It should be clarified that the attack targeted the “cross-chain bridge smart contract,” so the native DOT tokens on the Polkadot mainnet were not affected. The main cause of this vulnerability was that Hyperbridge’s EthereumHost contract failed to properly verify the authenticity of messages before passing cross-chain information to the TokenGateway.

Image source: X/@OnchainLens

Cross-chain bridges have always been the most vulnerable part of blockchain architecture because they hold management permissions over token contracts. Once the verification mechanism is breached, hackers can easily gain unlimited minting rights.

Attack methods: forging messages, seizing management rights, unlimited minting

On-chain tracking shows that the hacker submitted a forged message via dispatchIncoming and successfully directed it to TokenGateway.onAccept. The system was supposed to verify the authenticity of this message based on the status on the Polkadot chain, but the verification mechanism recorded the promise value as “all zero,” meaning the verification process was completely bypassed or nonexistent. As a result, the system mistakenly treated this fake message as a legitimate command.

The accepted message immediately executed the changeAdmin function on the bridge’s Polkadot token contract, transferring admin rights to the attacker’s address. After gaining management control, the attacker minted 1 billion DOT tokens in a single transaction, then used Odos Router V3 to deposit these tokens into the DOT-ETH trading pool on Uniswap V4. After multiple exchanges at slightly different prices, they ultimately withdrew about 108.2 ETH.

“Liquidity shortage” becomes a protective shield

In financial markets, “liquidity shortage” is usually a headache for big whales, but ironically, this time the liquidity shortage became an invisible shield, greatly limiting the hacker’s profit potential.

Because the liquidity depth of DOT on Ethereum is extremely limited, it cannot absorb the 1 billion tokens minted out of thin air. When the hacker hurried to sell for cash, severe slippage caused the actual price per token to fall below 1 cent.

In a market with deeper liquidity or higher-value bridging assets, the same vulnerability could cause losses dozens of times greater. As of writing, DOT’s trading price is about $1.17, down 5% in the past 24 hours.

This incident once again illustrates that even if hackers have “unlimited minting rights,” whether they can successfully arbitrage ultimately depends on market liquidity and trading depth. The well-known blockchain security firm CertiK later confirmed the attack and stated that the hacker profited about $237k by minting and selling the bridge tokens.

As of now, Hyperbridge has not issued any public statement regarding the hacker incident.

Image source: X/@CertiKAlert

• This article is reprinted with permission from: 《BlockCast》
• Original title: “The Most Ridiculous Heist? Hacker Mints $1 Billion in $DOT, Only Steals $237K Due to ‘This Reason’”
• Original author: Block Sister MEL