Address Space Layout Randomization (ASLR) is a memory-protection technique that places code, stack, heap, and shared libraries at unpredictable addresses each time a program starts. By removing fixed memory locations, ASLR makes it harder for an attacker to turn a bug such as a buffer overflow or memory corruption into reliable code execution.
ASLR matters because many real exploits depend on knowing where useful data or instructions live in memory. When ASLR is enabled, attackers often need an additional information leak or another bypass to succeed; when it is disabled or weak, exploitation becomes much easier and more repeatable. Defenders rely on ASLR as a baseline hardening control in servers, browsers, and other exposed services, but it works best alongside other mitigations such as DEP/NX, stack canaries, and timely patching.