Buffer overflow — Linux Process — Stack Creation and Inspection

Process and what happens during process creation have been discussed in this post previously — https://medium.com/@raaki-88/linux-process-what-happens-under-the-hood-49e8bcf6173c

Now, let's understand what is buffer overflow:

A buffer overflow is a type of software vulnerability that occurs when a program tries to store more data in a buffer (a temporary storage area) than it can hold. This can cause the program to overwrite adjacent memory locations, potentially leading to the execution of malicious code or the crashing of the program. Buffer overflow attacks are a common method used by hackers to gain unauthorized access to a system.

Generally, C and C++ languages are more vulnerable to Buffer Overflow while programming languages like Python and Go have implementations which protect stack.

I have written the program in Python but had to use underlying C functionality to achieve similarly.

#!/usr/bin/python3
import ctypes
import pdb
buffer = ctypes.create_string_buffer(8) 
ctypes.memmove(buffer, b"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",1000)
print('end of the program')

This is a very simple implementation where we created a buffer which can hold 8 bytes of memory, next we will create a new object which moves from one block of the memory to another but with a newer size, which will create a segmentation fault here, where in ‘A’ string will be attempted…