Day 5: Overwriting the Return Address

Overwriting the Return Address

By overflowing a buffer, it’s possible to overwrite the return address on the stack. This allows an attacker to redirect program execution to a different location, such as malicious code. This is a foundational concept in many types of exploits, including Return-Oriented Programming (ROP).

Theory

Exploiting the Return Address

Objective: Learn how to overwrite the return address to control program execution.

Return Address Overwrite Exploitation: Read Here

Overwriting the return address is a powerful technique that allows an attacker to hijack the flow of a program, redirecting it to execute arbitrary code. This technique is often used in conjunction with other vulnerabilities to achieve code execution.

Practice

Hands-On Exercise

Practice on a vulnerable program: Use a vulnerable program (like a simple buffer overflow example) and GDB to practice overflowing the buffer and overwriting the return address. Try to make the program return to a function of your choice. Write a simple exploit: Create a Python script to generate the payload that overwrites the return address with a specific value. Use this script to automate the process of creating the exploit. Explore Return-Oriented Programming (ROP): Research ROP and try to use a series of “gadgets” (small sequences of instructions that end in a return) to chain together an exploit.