ASLRhyökkäykset

ASLRhyökkäykset refers to attacks that bypass or circumvent Address Space Layout Randomization (ASLR). ASLR is a security technique that randomizes the memory addresses where critical program components, such as the executable, libraries, and the stack, are loaded. This makes it harder for attackers to predict target memory locations for exploits, particularly those involving buffer overflows.

Despite ASLR's effectiveness, several methods have been developed to undermine it. One common approach is information leakage. Attackers may find vulnerabilities that allow them to read memory addresses from the process, effectively de-randomizing a portion of the address space. This can be achieved through format string bugs or other memory reading flaws.

Another technique involves brute-forcing. If the randomization is not sufficiently strong or if the attacker can trigger multiple crashes and restarts of the target program, they might be able to guess the correct addresses through repeated attempts. This is more feasible on systems with less entropy or on 32-bit architectures where the address space is smaller.

Some ASLR bypasses exploit predictable behavior in shared libraries or the operating system itself. If an attacker can reliably determine the base address of a commonly used library, they can then calculate the addresses of other functions within that library. Heap spraying and return-to-libc attacks, when combined with an information leak or partial de-randomization, can also be used to bypass ASLR. Modern systems employ enhanced ASLR techniques and other mitigations to make these attacks more difficult.