The fourth principle of defensive programming addresses a common issue: the mutability of a program's states, which can lead to unforeseen security bugs. Often, a program's state is mutable due to coding convenience. However, this convenience comes at the heavy cost of security vulnerabilities. We will first formalise this issue, then define the principle, followed by two implementation techniques.
Mutable objects and non-atomic operations can result in security vulnerabilities. Mutable variables can lead to unexpected changes in the state and race conditions, let's explore how to resolve this.
Lets look at some ways to implement immutability and ensuring data integrity, availability, and thread safety.
Let's explore a technique for ensuring an object remains unchanged within the code and protect it against unexpected state changes in multi-threaded environments.
Let's discuss a concept which can be context-dependent.
