First Flight #2: Puppy Raffle

Summary

The contract does not implement access control for critical functions such as selectWinner, refund, and changeFeeAddress. Any user can call these functions, which could result in undesired actions and potential financial losses.

Vulnerability Details

Access control mechanisms are essential for ensuring that only authorized parties can call critical functions within a smart contract. Without access control, the contract is vulnerable to unauthorized or malicious interactions, potentially leading to financial losses or unintended changes in contract state.

Impact

In the contract, there is no mechanism to restrict access to critical functions. For example, the selectWinner function can be called by any user, not just the owner or authorized parties. An unauthorized user could potentially disrupt the intended operation of the contract by invoking these functions.

The lack of access control exposes the contract to potential misuse, interference, or abuse by unauthorized users. This could result in financial losses or disruptions to the intended operation of the contract.

Tools Used

Manual Code Review

Recommendations

To address this vulnerability, it is recommended to implement access control for critical functions. You can use the OpenZeppelin Ownable pattern to easily add access control to your contract. Here's how you can do it:

1. Import the Ownable contract from OpenZeppelin:

2. Inherit the Ownable contract in your contract declaration:

3. Apply access control by using the onlyOwner modifier to restrict access to the owner of the contract. For example:

4. Apply the onlyOwner modifier to other critical functions like refund and changeFeeAddress as needed.

By implementing access control with the Ownable pattern, you ensure that only the owner of the contract can execute critical functions, reducing the risk of unauthorized or malicious access. This helps protect the contract's integrity and the funds associated with it.