First Flight #2: Puppy Raffle

Vulnerability Details

The refund function sets the address of a player who has requested a refund to the zero address (0x0) instead of removing it from the players array. This poses a risk in the selectWinner function, which could mistakenly select the zero address as a winner.

In the selectWinner function, the winner is randomly selected from the players array, which could include these zero addresses:

Impact

• Potential Loss of Prize Pool: If a zero address is selected as a winner, the prize pool is sent to an inaccessible address, resulting in a loss of funds.

• Reduced Trust in Raffle Integrity: The possibility of a non-participant (zero address) winning can undermine the integrity and fairness of the raffle.

• Inefficient Use of Resources: Maintaining zero addresses in the players array leads to wastage of storage space and unnecessary processing during winner selection.

Recommendations

• Remove Refunded Players from Array: Instead of setting a player's address to zero, remove the player from the players array upon a successful refund.

• Implement Checks in Winner Selection: Add additional checks in the selectWinner function to ensure that the selected winner is not a zero address. If a zero address is selected, the function should repeat the selection process or skip to the next valid address.