What is the benefit of an operating system (OS) feature that is designed to prevent an application from executing code from a non-executable memory region?

Identifying missing security patches is the function of a vulnerability scanner or patch management tool, not a memory execution protection feature like DEP.

Memory-resident viruses propagate through different mechanisms such as infecting files or hooking system calls; DEP does not specifically target their propagation, and many such viruses reside in executable memory regions anyway.

Polymorphic viruses use encryption and code mutation to evade signature detection, which is countered by heuristic or behavioral antivirus engines, not by non-executable memory region enforcement.

Data Execution Prevention (DEP) works by marking memory regions such as the stack and heap as non-executable, so even if an attacker successfully injects shellcode into a buffer, the CPU will refuse to execute it. This directly mitigates buffer overflow exploits and heap spray attacks where malicious code is stored in data buffers and then triggered. DEP is a hardware- and software-enforced protection that specifically targets this class of memory corruption vulnerability.