Summary

The function changeOwnercan be called by anyone.

Vulnerability Details

On line 111 of the code, the changeOwner function does not implement proper access control, allowing any user to set the owner of the contract to any arbitrary address.

Impact

An attacker can call the changeOwner function to take ownership of the contract. Once ownership is gained, the attacker can set the box price, add rewards, and worst of all, call the withdrawFunds function to steal all contract funds.

Tools Used

Manual inspection.

Recommendations

Implement access control to restrict the changeOwner function to the current owner only. This can be done by adding a require statement:

Alternatively, use a modifier and a custom error for better readability and gas optimization:

Apply the onlyOwner modifier to other functions that require ownership control. Additionally, since the function is called externally, it should be marked as external instead of public.