- Amount Lost: $47,600,000.00
- Funds Returned: $0.00
- Category: Borrowing and Lending
- Date: 2021-11-5
Quick Summary
The private key controlling BSC and Polygon deployments was compromised, allowing attackers to transfer ownership of the core bZx contracts and withdraw users' deposited collateral.
Details of the Exploit
The attackers initiated the exploit by transferring ownership of the core bZx contracts. This was done by invoking the target contract with a method through a fallback function with delegatecall. This allowed the attackers to withdraw users' deposited collateral from interest iTokens into another address. The same method was used on the Polygon chain.
Involved addresses:
- Exploiter 1: 0x74487eed1e67f4787e8c0570e8d5d168a05254d4
- Exploiter 2: 0x0acc0e5faa09cb1976237c3a9af3d3d4b2f35fa5
- Exploiter 3: 0x967bb571f0fc9ee79c892abf9f99233aa1737e31
- Exploiter 4: 0x6551fb9be444987f7482012cbf7ea95a1ee8dd0e
Block Data Reference
The transaction behind the attack:
- setTerget(): https://bscscan.com/tx/0x57e4aa5f2303a0ad4d1d74b1f33ba08a7ae2bf33cb1fa13870230779a3d52199
- transferOwnership(): https://bscscan.com/tx/0x9b16f5e8a648f72be3f9657880b26e525018e40e8873a14161690f8f48bf01b9
- iDOGE => DOGE: https://bscscan.com/tx/0xd1cff35db2583a2b3a239195c4567c8b63589079f8a1a9bdd0ef88a75b1ec18d
- iETH => ETH: https://bscscan.com/tx/0xa288f212bb84d0fa21274d93bc562ad4ecb4c702ff136ba897bbb65d0e50ca88
- iBNB => BNB: https://bscscan.com/tx/0x2dbb3df6959ba95da3bec8f618a3014f0d14e16816f2502e16d21e24e2597b6a
Proof Links: