How much was lost in the MoonHacker hack?

The MoonHacker hack resulted in $300K in losses on January 02, 2025.

What attack technique was used in the MoonHacker exploit?

The MoonHacker exploit utilized Unchecked FlashLoan Approve 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.

MoonHacker Hack

TOTAL LOST $300K

Low Jan 02, 2025 Unchecked FlashLoan Approve Exploit optimism

Affected Chain optimism Incident surface

Recovered - No recovery reported

All-Time Rank #1143 By amount stolen

Year 2025 Incident year

Incident Report

Protocol / Project MoonHacker

Date of Incident January 02, 2025

Affected Chain(s) optimism

Attack Technique Unchecked FlashLoan Approve Exploit

Classification Protocol Logic

Primary Source View Post-Mortem

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 unchecked flashloan approve exploit and Solidity and EVM internals

Capital Required Seed capital to cover gas and initial position setup

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

Protocol Analysis Identification of the exploitable vulnerability in MoonHacker'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 Unchecked FlashLoan Approve Exploit audit checklist and test coverage

If you're auditing a protocol with similar architecture to MoonHacker, these are the critical security checks that could have prevented this incident (January 2025).

Verify all logic paths related to Unchecked FlashLoan Approve Exploit 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.

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Related Attack Classes

The technique used in this hack maps to these vulnerability classes in our security curriculum:

See all Flash Loans Attacks examples →

Flash Loans Attacks

Proof-of-Concept Exploits

1 PoC available

poc-exploits - moonhacker

$ Moonhacker improper input validation

On-Chain Evidence & References

Reference https://blog.solidityscan.com/moonhacker-vault-hack-analysis-ab1…

Sources & References

01
Source 1 https://x.com/dedaub/status/1874838342485102852

Threat Assessment

Severity Level

LOW

Attack Vector Unchecked FlashLoan Approve Exploit
Root Cause Protocol Logic
Year 2025

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