Hardening measures can include setting up intrusion prevention systems, disabling accounts, reducing file system permissions and using encrypted network connections.
Binary hardening is independent of compilers and involves the entire toolchain.
The advantage of manipulating binaries is that vulnerabilities in legacy code can be fixed automatically without the need for source code, which may be unavailable or obfuscated.
Secondly, the same techniques can be applied to binaries from multiple compilers, some of which may be less secure than others.
Binary hardening often involves the non-deterministic modification of control flow and instruction addresses so as to prevent attackers from successfully reusing program code to perform exploits.