Incident Overview
PancakeBunny's VaultFlipToFlip vault was exploited using 8 flash loans, leading to a skewed calculation of the BUNNY price and a loss of approximately $1B in BUNNY tokens.
The attacker manipulated the price on various PancakeSwap pools using 8 flash loans, which skewed the calculation of the BUNNY price in the VaultFliptoFlip vault. They borrowed WBNB from seven different PancakeSwap pools and USDT from Fortube Bank, deposited a portion of these funds into the WBNB+BUSDT pool, and swapped a large amount of WBNB for BUSDT. This manipulation allowed them to claim a reward of 6.97M BUNNY, valued at about $1B, from VaultFlipToFlip. After the exploit, they returned the flash loans to the PancakeSwap pools and Fortube Bank.
Stolen funds:
- 6.97M BUNNY (~$1B)
The attacker's address:
https://bscscan.com/address/0xa0acc615…d7e187
The transaction behind the attack:
https://bscscan.com/tx/0x897c2de7…e6a979
Incident Report
Protocol Information
Market Context at Time of Hack
What the Attacker Needed to Succeed
Understanding the prerequisites for this type of attack helps auditors identify protocols that are most at risk and helps developers build better defenses.
What Auditors Should Check
If you're auditing a protocol with similar architecture to PancakeBunny, these are the critical security checks that could have prevented this incident (July 2021).
- Verify all logic paths related to Flash Loan Attack are guarded by proper access controls and input validation - see the Flash Loans Attacks attack class for patterns
- Review privileged functions (owner, admin, governance) for potential abuse vectors - centralization risks should be documented and bounded with timelocks or multi-sigs
Master these auditing techniques with hands-on labs and real exploit scenarios in the Smart Contract Hacking course.
Free TrialFunds Recovery
Recovered
$2.4M
Net Loss
0
Related Attack Classes
The technique used in this hack maps to these vulnerability classes in our security curriculum:
Sources & References
- 01
- 02
- 03
- 04
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