Thread by @CertiKAlert

We are seeing a possible exploit on @BeanstalkFarms - symbol $BEAN which has dropped 100%

#slippage

Address: 0xdc59ac4fefa32293a95889dc396682858d52e5db0x48f33863b1defc7b294717498c634ba9a5fb58a7

Be careful out there!

Flashloan attack on Beanstalk has drained their fund of approx $100 Million

Attacker wallet: etherscan.io/txs?a=0x1c5dcd…

“Publius” the discord owner has stated the project has no money to carry on and ‘its dead’.

The hacker has moved roughly $30M (~9700 #ETH) to @TornadoCash

Follow the funds yourself with SkyTrace: certik.com/skytrace/eth:0…

Attack Flow

1. The attacker flashloaned 350M $Dai, 500M $USDC, 150M $USDT, 32M $Bean, 11.6M $LUSD

2. Attacker then added the flashloaned amount (~350M Dai, 500M USDC, 150M USDT) to Curve.fi pool as liquidity and received 979,691,328 DAI/USDC/USDT(3Crv) LP tokens

3. The Attacker used all the gained assets from the flashloan to vote the #BIP18 proposal.

4. After passing the proposal, they immediately invoked the emergencyCommit() to execute the BIP18 proposal.

5. the attacker was then able to drain the 36,084,584 $BEAN, 0.54 UNIV2(BEAN-WETH), 874,663,982 BEAN3Crv and 60,562,844 BEANLUSD-f.

6. The attacker used the drained assets (in Step5) to repay the #flashloan

The root cause of the exploit is that the BEAN3Crv-f and BEANLUSD-f (used for voting) in the Silo system could be created via flashloan.

Due to the lack of an anti-flashloan mechanism in the Beanstalk protocol, the attackers were able to borrow tokens that are supported by the protocol and voted for malicious proposals.