Incident Overview
On May 29, 2026, the LegendaryMoneyMonNft contract was exploited on the BNB Chain for 85000 USD. The attacker capitalized on a signature validation flaw that allowed them to pass a malformed signature to bypass security checks, falsely claim rewards, and drain the contract's treasury.
The exploit targeted a flawed signature check in the contract's claimReward function, which authenticated requests by ensuring recoverSigner(...) == admin. In Solidity, if ecrecover receives a malformed signature, it fails and outputs address(0). The attacker first ensured the contract's admin variable was set to address(0).
They then submitted a completely invalid signature, forcing the recovery function to return the zero address. The contract evaluated address(0) == address(0) as valid, giving the attacker administrative clearance to mint and claim all available reward tokens, which they immediately swapped for USDT on PancakeSwap.
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 MoneyMon, these are the critical security checks that could have prevented this incident (May 2026).
- Verify all logic paths related to Other 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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