How much was lost in the Onyx V2 hack?

The Onyx V2 hack resulted in $4.0M in losses on September 26, 2024.

What attack technique was used in the Onyx V2 exploit?

The Onyx V2 exploit utilized Liquidation Logic Exploit. Understanding this attack vector is critical for smart contract auditors and developers building secure DeFi protocols.

How can developers prevent similar smart contract attacks?

Preventing smart contract hacks requires a combination of secure coding practices, thorough security audits, and understanding common attack vectors like reentrancy, oracle manipulation, and access control flaws. Smart Contract Hacking (SCH) provides hands-on training to help developers and auditors identify and prevent vulnerabilities before deployment.

Onyx V2 Hack

TOTAL LOST $4.0M

Medium Sep 26, 2024 Liquidation Logic Exploit ethereum

Affected Chain ethereum Incident surface

Recovered - No recovery reported

All-Time Rank #472 By amount stolen

Protocol Type Lending Target category

Incident Overview

Onyx is the Backbone of Decentralised Web3 Protocols

Incident Report

Protocol / Project Onyx V2

Date of Incident September 26, 2024

Affected Chain(s) ethereum

Attack Technique Liquidation Logic Exploit

Classification Protocol Logic

Primary Source View Post-Mortem

Protocol Information

Protocol Type Lending

Smart Contract Language Solidity

Official Website app.onyx.org

Protocol Twitter/X @OnyxDAO

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.

Technical Knowledge Deep understanding of liquidation logic exploit and Solidity and EVM internals

Capital Required Seed capital to cover gas and initial position setup

On-Chain Access Ability to interact with ethereum smart contracts and deploy a custom exploit contract

Protocol Analysis Identification of the exploitable vulnerability in Onyx V2's contract logic - root cause: protocol logic

Execution Speed Precise transaction ordering and timing to exploit the vulnerability within a single atomic block

Obfuscation Plan A strategy to launder and move stolen funds - typically through mixers, cross-chain bridges, or decentralized DEX swaps to resist tracing

What Auditors Should Check

Could this have been caught in audit? Likely — with a thorough Liquidation Logic Exploit audit checklist and test coverage

If you're auditing a protocol with similar architecture to Onyx V2, these are the critical security checks that could have prevented this incident (September 2024).

Verify all logic paths related to Liquidation Logic Exploit are guarded by proper access controls and input validation
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.

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Sources & References

01
Source 1 https://x.com/blocksecteam/status/1839314277359849484

Threat Assessment

Severity Level

MEDIUM

Attack Vector Liquidation Logic Exploit
Root Cause Protocol Logic
Year 2024

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