Sparkn

Summary

Tokens such as USDT and USDC allow blacklisting which may cause distribute() to fail.

Vulnerability Details

Prize distribution will fail because of blacklisted users. If signature mechanism is used this will be really painful. If there are multiple blacklisted accounts which may happen if there are a lot winners this will be a lot of pain.

Impact

Prize distribution will fail which is lost funds on txn fees for organizer/owner. And a lot of pain if signature scheme is used and there multiple banned accounts.

Tools Used

Recommendations

Use merkle trees for distributing prizes. The contract will only store the root of the tree and have a claim method which verifies a proof sent by a user.