What is the main danger if a private helper task inside a contract is accidentally made public for anyone to use?
The main danger if a private helper task inside a contract is accidentally made public for anyone to use is a critical breach of access control, allowing unauthorized execution of sensitive operations. A private helper task is a function designed to be called only by other functions within the same contract; it cannot be invoked directly by external accounts or other contracts. Its purpose is typically to manage internal state, perform sensitive sub-routines, or execute operations not intended for direct external interaction. When such a function is mistakenly declared as public, its visibility changes, enabling any external address, including an attacker's wallet or another contract, to directly call and execute it. This exposes functionalities that were intended to be protected and only accessible under specific, controlled conditions. The consequence is that an attacker can call this newly exposed public function to perform actions that were meant to be restricted, leading to severe outcomes. For instance, if the private helper task was responsible for critical state changes, such as modifying the contract's owner, changing key configuration parameters, transferring assets, or draining funds, an attacker can now trigger these actions at will. This could result in the complete loss of funds or digital assets stored in the contract, a transfer of contract ownership to the attacker, or the manipulation of core contract logic, effectively subverting the contract's intended functionality and security model. For example, a function like `_transferInternalFunds(address to, uint amount)` which was designed to move funds within the contract's internal logic, if made public, could be called by an attacker to send all contract funds to their own address without authorization.