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[0] pointer to format string (our input) [1] saved %rbp of main [2] saved RIP of main <-- target [3...] other registers / args By printing many %p s we can see where the saved RIP lands. Example payload:

# Target location: saved RIP on stack (found via %p leaks) ret_addr = 0x7fffffffe0a8 # example address from a local run https- bit.ly crackfire

base = leaked_puts_addr - puts_offset_in_binary For the purpose of this write‑up we’ll assume the binary’s base is 0x555555554000 (typical ASLR value on my system). All subsequent addresses are . 6. Locating the return address on the stack When printf(buf) processes the format string, the stack layout looks like: [0] pointer to format string (our input) [1]

0x555555555580 0x7fffffffde10 0x555555554b40 0x555555554b88 ... The pointer ( 0x555555554b40 ) matches the address of the saved RIP (confirmed by comparing to gdb ’s info frame ). https- bit.ly crackfire