Exam CAS-005 topic 1 question 39 discussion

Why the other options are incorrect: A. TPM (Trusted Platform Module): Used for secure hardware-based storage and cryptographic functions, but not directly related to memory execution protection. B. Secure boot: Ensures that the OS boots using trusted software only, but doesn’t control memory execution behavior at runtime. D. HSM (Hardware Security Module): Used for secure cryptographic key storage and operations, unrelated to memory protection or application-level exploit mitigations.

Explanation: The mprotect() system call allows a program to change the memory protection of a region of memory — for example, marking certain areas as non-executable to prevent code execution from those regions. This is a mitigation technique commonly used against buffer overflow and code injection attacks. To make this protection effective, the system must support and enforce non-executable memory regions, which is exactly what the NX bit (No eXecute bit) does. ✅ NX bit: Hardware-level feature that marks memory pages as non-executable. Helps prevent execution of code from data regions like the stack or heap. Complements the mprotect() system call to enforce memory safety.