format-string-exploitation

To exploit a format string vulnerability for a GOT overwrite, you compute specific padding values and use %n, %hn, or %hhn format specifiers to write target addresses directly into the Global Offset Table.

Calculating padding for %n writes involves identifying the exact offset of your input on the stack and formatting the string with the correct width specifiers to output the precise byte count needed for the target memory address.

Bypassing FORTIFY_SOURCE positional write restrictions involves using direct parameter access specifiers to manipulate the stack pointer chain, allowing writes even when standard %n usage is restricted by compile-time protections.

Handling 64-bit null-byte constraints in format string exploitation requires placing target addresses after the format specifiers in the payload, preventing premature string termination caused by null bytes in high memory addresses.

Yes, you can use pwntools automation approaches like fmtstr_payload and FmtStr to build reliable memory primitives and generate exploit payloads for blind remote format string targets without source code.

Leaking stack canaries and libc pointers via a printf vulnerability uses attacker-controlled format specifiers like %p to read sequential stack values and dereference pointers to disclose memory layout information.