Bad Memories -v0.9- -recreation- Now

(gdb) call ((void(*)(char*))0x401456)(0x6020a0+8) Or simply:

[0x00401234]> afl | grep secret 0x00401456 sym.secret_function Disassemble secret_function :

strings core.dump | grep -i ctf Returns: Bad Memories -v0.9- -recreation-

But it’s never called normally. The challenge name "Bad Memories" + -recreation- hints we need to force a UAF to redirect execution to this function. Examine heap chunks in the core dump.

Check with radare2 :

Using gdb with the core file:

gdb -c core.dump (gdb) dump memory recovered.bin 0x400000 0x401000 # typical .text section But better: use volatility (if full memory dump) or memdump from /proc/pid/maps style. Check with radare2 : Using gdb with the

In GDB, call the overwritten function:

void secret_function() char flag[64]; FILE *f = fopen("flag.txt", "r"); fread(flag, 1, 64, f); flag[strcspn(flag, "\n")] = 0; printf("Flag: %s\n", flag); FILE *f = fopen("flag.txt"

Also found references to malloc , free , heap , and flag.txt . Since only the core dump was given (no original binary), we need to recreate the binary or at least its memory layout.