Submission Details
Severity:
use of on-chain source of randomness
Summary
In selectWinner() on-chain data are used to randomnly generate winnerIndex and rarity
Vulnerability Details
msg.sender, block.timestamp and block.difficulty can be used to manipulate winnerIndex and rarity and set them to a desirated values. That's makes the raffle gamable by a malicious player
Impact
The draw can be rigged
Tools Used
Manual review
Recommendations
Use decentralized oracle networks like chainlink to generate and compute random numbers
Updates
Lead Judging Commences
Hamiltonite 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
Live
The contest is live. Earn rewards by submitting a finding.
Appeals
This is your time to appeal against judgements on your submissions.
Appeals Review
Appeals are being carefully reviewed by our judges.