Defenses: Hardening in Depth

• FORTIFY_SOURCE (-D_FORTIFY_SOURCE=2): the libc *printf variants refuse %n in writable format strings and add bounds checks —- kills the classic %n write in many cases.
• RELRO:
• Partial RELRO: reorders sections, but GOT still writable.
• Full RELRO (-Wl,-z,relro,-z,now): resolves all symbols at load time and marks the GOT read-only —- defeats GOT overwrite.
• ASLR / PIE / stack canaries: still relevant, but remember a format leak is exactly what bypasses these —- so the code fix is the real defense.