ChainSwap Hack

Reported loss $4.4M
BNB Chain Ethereum
Other

What happened

On July 10, 2021, an attacker exploited ChainSwap's bridge contracts, directly minted bridged tokens, and sold them into BNB Chain liquidity. Contemporary reporting valued the attacker wallet at roughly $4.4 million. ChainSwap froze the Ethereum–BSC bridge and mapped tokens while affected projects responded.

How it happened

  1. The attacker exploited ChainSwap's bridge authorization path to mint bridged tokens.
  2. They repeatedly directed minted tokens to attacker-controlled addresses.
  3. The tokens were consolidated and sold on BNB Chain, including through PancakeSwap.
  4. ChainSwap froze bridge/mapped-token activity during response.

Protocol details

Classification Bridge / Bridge & Cross-Chain
Protocol Type Exploit/Other
Category Bridge Hack
Affected asset / contract ASAP
Implementation language Solidity
Protocol links Website @chain_swap

Evidence

Same attack technique

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