Day 0: Fuzzing A Game

0. Introduction

I choose this game for several reasons:

• An old (and therefore small) game is a perfect candidate for fuzzing.
• I'd like to do the same to the new version of the game ( difficulty options ).

In this blog we will be fuzzing:

• The Binary Executable
• The Network Protocols

1. Get The Game!

You can buy/download Counter-Strike 1.6 here.

2. Labortory Setup

1. Start WireShark
2. Start TCPView
3. Start Counter-Strike 1.6

The Counter-Strike 1.6 game engine is called GoldSource. The game engine also has a Software Development Kit (SDK), called Half-Life SDK.

I started the game and I created a server.

I created a Python script to print a table of process IDs, process names, and their associated network port numbers. Knowing the port numbers allows me to filter the network traffic! Here's the output of the script as a table:

Process ID	Process Name	Port
19112	hl.exe	58479
19112	hl.exe	57438
19112	hl.exe	27005
19112	hl.exe	27015
19112	hl.exe	7025

I updated the Python scirpt to generate WireShark Display Filters for the hl.exe ports.

  tcp.port == 58479 || tcp.port == 57438 || tcp.port == 27005 || tcp.port == 27015 || tcp.port == 27025

Hmm, that didn't seem to work.