Buffer overflow prevention techniques
There are many techniques implemented to avoid buffer overflow attacks. In the upcoming sections, we will cover some of the well-known mechanisms.
Address space layout randomization
Address space layout randomization (ASLR) is a defense mechanism developed by the Pax Project against buffer overflow attacks. This memory-protection process randomizes the executable location when loaded in memory. Because, as we learned in the previous sections, if locations are predictable, then system exploitation will be easy. It started as a Linux patch in 2001, but later was integrated in many other operating systems. ASLR can be defeated using the following techniques:
- Bruteforcing all the possible 256 addresses until the exploit works
- Generating block of NOPs until we get a legitimate memory
Stack canaries
Stack canaries are used to detect buffer overflow attacks before they occur. Not to prevent them exactly, but they are implemented by compilers to make the exploitation...
