Submission Details
Severity:
No randomness
Summary
There is no randomness in selecting the winner.
Vulnerability Details
In selectWinner function at line139
uint256 rarity = uint256(keccak256(abi.encodePacked(msg.sender, block.difficulty))) % 100;
The block.difficulty will not be changing in Proof of stake. So there won't be any randomness.
Impact
The winner can be predicted earlier.
Tools Used
Foundry
Git
Manual review
Recommendations
Avoid using static or predictable variables in generating random values.
Updates
Lead Judging Commences
patrickalphac almost 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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