Poly Network (2021) — Crypto Hack
Fully RecoveredAttacker exploited a flaw in Poly Network's cross-chain contract to override keeper role and transfer assets.
Summary
Attacker exploited a flaw in Poly Network's cross-chain contract to override keeper role and transfer assets.
How It Was Compromised — Bridge via Smart Contract Exploit
The attacker discovered a vulnerability in Poly Network's EthCrossChainManager contract that allowed them to pass a crafted transaction to change the keeper address to their own. By exploiting the _executeCrossChainTx function, they replaced the legitimate keeper with their address across Ethereum, BSC, and Polygon, then drained all funds.
Fund Flow & Laundering Analysis
In an unprecedented move, the attacker returned nearly all funds within two weeks, claiming it was a white-hat operation. Funds were returned to a multi-sig controlled jointly by Poly Network and the attacker. Final $33M USDT was frozen by Tether and returned.