Buffer overflow with saved return pointer overwrite

In this recipe, we will discuss exploiting an application with buffer overflow vulnerability and with a saved return pointer overwrite.

Getting ready

We can use FreeflotFTP as the vulnerable application. You can get the application from: https://rejahrehim.com/assets/sample-package/ftp_server_sample.zip.

The vulnerable machine environment is Windows XP. So run Windows XP in a real or virtual environment and install the Immunity Debugger in it.

Installing Mona

We need to install Mona, a pycommand module for the Immunity Debugger. To do this, download the mona.py from: https://github.com/corelan/mona.

Then, add the mona.py to the pyCommands folder inside Immunity Debugger application folder:

How to do it...

Follow the steps to create an exploit for buffer overflow attack:

1. In a Windows machine, start the Immunity Debugger and open the vulnerable application in it.
2. As it is an FTP server, we can try to crash the application by connecting it from another...