Submission Details
Severity:
On-chain data can be manipulated and used in attacker favor
Summary
On chain data should not be used to generate a random number since they could be manipulated by miners or validators
Vulnerability Details
If the vulnerability is exploited by a miner. The protocol can lose its fairness and the winner could be always determined alongside the NFT.
Impact
Funds and NFT loss.
Raffle fairness (McDonald lottery :).
Tools Used
Manual review
Recommendations
Consider using an Oracle like "Chainlink" which generates Verified Random Number (VRF) that cannot be expected or manipulated
Updates
Lead Judging Commences
Hamiltonite about 2 years ago
Submission Judgement Published Assigned finding tags:
weak-randomness
Root cause: bad RNG Impact: manipulate winner
Rewards breakdown
nSLOC
143This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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