How does data execution protection (DEP) help prevent a buffer overflow?

Data Execution Prevention (DEP) is a crucial security feature designed to prevent certain types of attacks, including buffer overflows, by marking specific areas of memory as non-executable. This means that if an application tries to execute code from a memory region that should only contain data, the operating system will terminate the process, thereby preventing the execution of potentially malicious code that could be injected during a buffer overflow attack.

By identifying areas of memory that are meant to execute code and explicitly preventing execution in segments of memory intended solely for data, DEP reduces the risk that an attacker can successfully execute arbitrary code that has been placed into these memory spaces through buffer overflows. This technique essentially creates a boundary that protects the integrity of the execution environment by ensuring that only legitimate code can run, effectively thwarting exploitation attempts that rely on manipulating memory regions.

In this way, DEP serves as an effective line of defense against buffer overflow attacks by controlling the execution rights of code within a program's memory space.