GDB

Pwncollege

Debuggers 

GDB / GNU Debugger

Debuggers, including gdb, observe the debugged program as it runs to expose information about its runtime behavior. 

You start a program with the starti command: (gdb) starti

starti “starts the program at the very first instruction.”

In the line mov rdi, 567800, you are moving the value 567800 into rdi, rather than reading memory at the address 567800. To read memory, you must enclose the value in [], such as: [567800].

Double dereference 

Solution 

mov rdi, [rax]
mov rdi, [rdi]
mov rax, 60
syscall