Save the bombk file zeus and unpack tar xvf bombk

Introduction

Step 1: Get Your Bomb

• bomb: The executable binary bomb. This executable will only run on zeus-1.cec.gmu.edu

• bomb.c: Source file with the bomb's main routine.

#include <stdio.h>

#include <stdlib.h>

// Access zeus-1.cec.gmu.edu

printf("First, access zeus-1.cec.gmu.edu using ssh and your GMU userid/password.\n");

printf("Enter your user name and GMU email address and hit the Submit button.\n");

printf("The server will build your bomb and return it to your browser in a tar file called bombk.tar,\n");

printf("- README: Identifies the bomb and its owner.\n");

printf("- bomb: The executable binary bomb, which will only run on zeus-1.cec.gmu.edu.\n");

You must do the assignment only on zeus (specifically, zeus-1; not any other machine or zeus-2!). In fact, there is a rumor that Dr. Evil really is evil, and the bomb will always blow up if run elsewhere. There are several other tamper-proofing devices built into the bomb as well, or so we hear. Your job for this project is to defuse your bomb. You can use several tools available to you on Zeus to help you defuse your bomb. Please look at the hints section for some tips and ideas. The best way is to use your favorite debugger gdb to step through the disassembled binary. (You may not use external tools to solve the bomb.) Each time your bomb explodes it notifies the bomb server, and you lose 1/2 point (up to a max of 10 points) in the final score for the project. So there are consequences to exploding the bomb. You must be careful! The first four phases are worth 15 points each. Phases 5 and 6 are a little more difficult, so they are worth 20 points each. So the maximum score you can get is 100 points. (Some of you may have heard about a “secret phase”... What secret phase?)

Although phases get progressively harder to defuse, the expertise you gain as you move from phase to phase should offset this difficulty. However, the last phase will challenge even the best students, so please don’t wait until the last minute to start.

To avoid accidentally detonating the bomb, you will need to learn how to use gdb to single-step through the assembly code and how to set breakpoints. You will also need to learn how to inspect both the registers and the memory states. One of the nice side-effects of doing the project is that you will get very good at using a debugger. This is a crucial skill that will pay big dividends the rest of your career.

Logistics

http://zeus-1.cec.gmu.edu:15225/scoreboard

This web page is updated continuously to show the progress of the class. Note that this web page is only

to find the right one. But this is no good for several reasons:

• You lose 1/2 point (up to a max of 10 points) every time you guess incorrectly and the bomb explodes.

on how to use them.

Provide complete answer for Part 2 with comments

// and figure out exactly what it does.

// This is a useful technique, but it may not be always easy to do.

// You may not modify your bomb in any way to defuse it.

printf("Don't modify your bomb in any way to defuse it.\n");

printf("There are many tools available to help you figure out both how your bomb works and what is wrong when it doesn't.\n");

return 0;