Incident Overview
Vulnerability in Vyper Compiler exploited, causing a loss of 50,476,970 USD across multiple projects.
The Vyper Compiler, a tool designed for writing smart contracts on EVM-compatible chains, suffered a significant exploit due to a vulnerability in versions 0.2.15 to 0.3.0. Independent security researchers confirmed that the vulnerability was fixed since version 0.3.1. The root cause was separate Reentrancy Lock slots in add_liquidity and remove_liquidity functions in Curve Pools, implemented in the vulnerable Vyper versions, allowing a reentrancy attack.
This exploit affected several projects including MetronomeDAO, JPEG'd, Alchemix, and Curve Pools, resulting in a combined loss of 50,476,970 USD. Some funds were returned, totaling 6,820,757 USD.
Curve Pools:
Exploiters:
https://etherscan.io/address/0xb752def3…41b324
https://etherscan.io/address/0xc0ffeeba…f29671
Malicious Transactions:
https://etherscan.io/tx/0xcd99fadd…ae2052
https://etherscan.io/tx/0x2e7dc8b2…ae477c
Funds Returning Transaction:
https://etherscan.io/tx/0xb7675412…0954fd
JPEG'd:
Exploiter:
https://etherscan.io/address/0x6ec21d18…978538
Malicious Transaction:
https://etherscan.io/tx/0xa84aa065…f1620c
Alchemix:
Exploiter:
https://etherscan.io/address/0xdce5d6b4…75d7d8
Malicious Transaction:
https://etherscan.io/tx/0xb676d789…3c9801
MetronomeDAO:
Exploiter:
https://etherscan.io/address/0xc0ffeeba…f29671
Malicious Transaction:
https://etherscan.io/tx/0xc93eb238…400964
Funds Returning Transaction:
https://etherscan.io/tx/0x650a73bf…469f9a
Incident Report
Protocol Information
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 Vyper, these are the critical security checks that could have prevented this incident (July 2023).
- Verify all logic paths related to Reentrancy are guarded by proper access controls and input validation - see the Reentrancy attack class for patterns
- Check that all state-changing functions follow the Checks-Effects-Interactions (CEI) pattern to prevent reentrancy and logic ordering bugs
- 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
$6.8M
Net Loss
43662579
Related Attack Classes
The technique used in this hack maps to these vulnerability classes in our security curriculum:
Sources & References
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