Mystery Box

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The `changeOwner()` function in the protocol allows any user to change the ownership of the contract. This introduces a significant security vulnerability, as malicious users can take control of the contract by simply calling the function. Proper access control needs to be enforced to ensure only the current owner can change the ownership.

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The current implementation of the `changeOwner()` function does not check whether the caller is the current owner of the contract. This means that any user can call this function and change the owner of the contract to themselves or another address. This is a severe security flaw, as it allows unauthorized access to the contract's critical functions.

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Allowing any user to change the contract's owner can lead to complete loss of control over the contract. The new owner could access restricted functions, withdraw funds, and manipulate the contract to their advantage, leading to the potential loss of user funds and trust in the protocol.

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Manual code review and Solidity testing framework (e.g., Foundry).

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To mitigate this issue, the `changeOwner()` function should be restricted so that only the current owner of the contract can call it. This can be achieved by adding an ownership check using a `require` statement.

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Here is the updated `changeOwner()` function:

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function changeOwner(address _newOwner) public {

+ require(msg.sender == owner, "Only the owner can change ownership");

}