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Project 8 (Buffer Overflow)

UNDER CONSTRUCTION FALL 2016 - DO NOT BEGIN YET

Objectives

  • Use a debugger to examine assembly code and stack memory
  • Conduct simple buffer overflow attacks against a vulnerable program from the command line

Resources

The CS department has prepared a VM for each of you to be able to use on the lab machines or your own machine. You need to be connected to the CS network to download the actual VM. Instructions

For tips on how to use GDB, here is a document detailing some of the more useful and important commands. Ignore the comments on the Bomb lab: it may become a lab later in the semester but you don't have to worry about it now.

Part 1

This part is intended to introduce you to the debugger, understand how to examine and update memory locations using a debugger, and gain experience with how the runtime stack is organized. A helpful way to start is to watch an introductory video on buffer overflow attacks. The following file makes a series of function calls main → freshman → sophomore → junior → senior. Compile the program and run it in the debugger, breaking somewhere in function senior. Print out all of the stack activation frames, and label as many memory locations as you can. You should be able to identify 1) return addresses, 2) saved frame pointers (ebp), 3) local variables, 4) function arguments. You may print out a hard copy, write on it to label all the items, and turn in the hard copy. You may also submit your result electronically.

  • Compile the program with the -m32 compiler option. We will use a 32-bit program for simplicity.

Part 2

I used a collection of files based on materials found in Jon Erickson's The Art of Exploitation. Visit the following page for hints on using gdb and perl, and then try a range of options to change to flow control for a program.

  • Complete Sections A, B, C in the Resources File
    • Section C - From the command line, gain access to the program without providing a legitimate password.
    • Take a screen shot of your result for Section C and submit that to Learning Suite.

Extra Credit Options

Option 3

The most recent CS 360 course now includes a project on buffer overflow attacks. This is based on a lab developed at Syracuse. You may complete that lab and submit the result for Project 8.

Option 4 (NOT AVAILABLE - Now Extra Credit Lab)

For this option you can practice your buffer overflow skills against the Carnegie Mellon buflab. This lab is a part of EE 324 as well. Currently we do not have a project description posted. However the one for EE 324 is here and it is the same as what you will be doing here. However please note that you cannot work in teams, despite what that spec says. For your cookie provide your NetID. This lab can only be done on CS lab machines (not SPICE machines like the spec says). You can SSH into them if you don't want to go into the labs.

Get your bomb here. See the results board here.

Option 5

Find resources on the web to help you develop your own shell code and perform a stack smashing attack with your own shellcode instead of taking existing shellcode and using it without understanding what it does.

Option 6

Choose a compiler and O/S and reverse engineer the canary-based stack protection to learn how it works. How does it compare to the canary alternatives we discuessed in class? Demonstrate how it works to detect a stack-smashing attack.

Option 7

Learn about format string vulnerabilities and demonstrate how they work.

cs-465/project-8-buffer-overflow.1478629121.txt.gz · Last modified: 2016/11/08 11:18 by seamons
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