In software development, a NULL pointer is a pointer variable that does not reference any valid memory location. Dereferencing such a pointer—attempting to access the memory it supposedly points to—results in undefined behaviour. In many systems, this leads to crashes, data corruption, or even exploitable vulnerabilities.
Extraneous functionality can be defined as any feature or functionality that is present in a mobile application but is either unintentional or no longer needed. It may be left over from earlier stages of the development process, such as during testing or debugging, or added for convenience but overlooked as the application moves closer to production. Regardless of the reason for its existence, extraneous functionality represents a security risk.