HW3

Web Security Project

Prerequisites

For this project, you are going to use a virtual machine running (an ancient) version of Linux. We provide basic VM images for both Oracle VirtualBox and VMware. CSL Linux machines all have VirtualBox pre-installed.

• Download Oracle's Virtual Box: https://www.virtualbox.org/wiki/Downloads (Links to an external site.)
• Download VMware: https://my.vmware.com/en/web/vmware/free#desktop_end_user_computing/vmware_workstation_player/12_0 (Links to an external site.)

VMware is only available free on Linux and Windows; if you have VMware fusion for Mac that may work as well.

Environment Setup

• Download the BoxesX virtual machine image Download virtual machine image (warning: 600 MB!). 
• The ova file should be loaded into VirtualBox or VMware. 
• The user name and password are 'user' and 'user'.

Highly Recommended Environment Setup: VNC Server and Client

To enable functionality such as copying and pasting from your host machine and being able to gracefully resize your window, we strongly recommend that you use a VNC client to interact with the virtual machine.

• Install a VNC client on your host machine. Any client should work; we recommend the open-source UltraVNC Links to an external site..
• Make sure that your virtual machine has the following port forwarding option:

Refer to homework 1 if you want to know how to set up a port forwarding option.

• After logging into the virtual machine, run the command vncserver :1 to start the server. The :1 makes sure that the server is listening on the correct port, so don't change it.
  • The first time you run this, the program will ask you to set a password for the server. You can run vncpasswd if you ever need to change it.
• Mac Users: Safari has a built in VNC client. To use Safari to connect to the VNC, go to vnc://127.0.0.1:8888
• Open your VNC client. Instruct the client to connect to 127.0.0.1:8888. However, be aware that using it may cause some crashing/freezing. A dedicated piece of VNC software is recommended.
• Input the password you set for the VNC server and you should see the screen.

Now that you have connected to the virtual machine using VNC, you can use the xclip command to copy and paste things from your host machine to the virtual machine. To copy the text of a file in the virtual machine, run xclip filename.

To set the size of your VNC window, add the parameter vncserver :1 -geometry 1920x1080, replacing 1920x1080 with whatever resolution you prefer.

How to run Iceweasel

The Web server serving the Zoobar site you will be attacking is hosted inside the VM. (If you try to connect to zoobar.org outside the VM, you will get Stanford's site, which you should not try to interact with.) Furthermore, the Web browser you'll use to develop and test your attacks is also hosted inside the VM. It is called Iceweasel.

Iceweasel is the Debian version of Firefox (essentially the same browser, but with a different name because of licensing issues). To start Iceweasel in BoxesX, login as user, and do the following:

1. If you are not using VNC, type the startx command. This will start the X Window System, and a new window will be displayed with a xterm (shell) where you can enter commands. (Click the mouse to place the window.)
2. Type iceweasel & within the xterm. This will open the Iceweasel browser. (Again, click the mouse to place the window.)
3. In the URL bar, you can type http://zoobar.org/ (Links to an external site.) to connect to the Zoobar site. As with any project, you will want to make and keep frequent backups of your work.

Project Overview

The fictional “Zoobar Foundation” has set up a simple Web application at zoobar.org (inside the BoxesX VM), allowing registered users to post profiles and transfer “zoobar” credits between each other. Each registered user starts with 10 "zoobar" credits.

You will craft a series of attacks on zoobar.org that exploit vulnerabilities in the website design. Each attack presents a distinct scenario with unique goals and constraints, although in some cases you may be able to reuse parts of your code.

Although many real-world attackers do not have the source code for the websites they are attacking, you are one of the lucky ones: you can find the source code under /var/zoobar/www in the BoxesX VM.

The Zoobar server is actually run locally on each of your boxes. We will run your attacks after wiping clean our own local database of registered users (except the user named “attacker”). Of course this means that any data you have added while working on the assignment will not be present during grading.

Before Start

Browser: We will grade your project within the BoxesX VM, using the Iceweasel browser,  which is installed in the Boxes. Therefore, you should test your code in the boxes on this browser. Iceweasel is essentially the same browser as Firefox, but under different branding. Anything that works in iceweasel will likely work in (the same version of) Firefox as well. There are subtle quirks in the way HTML and JavaScript are handled by different browsers, and some attacks that work in Internet Explorer (for example) may not work in Firefox (and therefore in Iceweasel). In particular, you should use the Mozilla way of adding listeners to events (see https://developer.mozilla.org/en/DOM/element.addEventListener (Links to an external site.)).

Email script: For Attack A, you will need a server-side script to automatically email information captured by your client-side JavaScript to your user account within the Boxes. We have provided this script for you. Please review the instructions at http://zoomail.org/sendmail.php (Links to an external site.) (open this url from within the Boxes) and use that URL in your attack scripts to send emails. Again, this server is also being run locally on your own boxes machine. To check your local email, use the mutt email client (type mutt in the shell to start the client, and follow the instructions).

Attack A: Cookie Theft (30 pts)

• Your solution is a URL starting with http://zoobar.org/users.php (Links to an external site.)?
• The grader will already be logged into zoobar.org before loading your URL.
• Your goal is to steal the document cookie and email it to yourself using the email script.
• When sending the email with the stolen document cookie, the group name of the email has to be set to your net ID.
• Except for the browser address bar (which can be different), the grader should see a page that looks exactly as it normally does when the grader visits users.php. No changes to the site appearance or extraneous text should be visible. Avoiding the red warning text is an important part of this attack. (Its ok if the page looks weird briefly before correcting itself.)
• Note: You need to log into Zoobar before you execute your attack. Otherwise the cookie will not exist and your attack will appear to do nothing.
• Hint: Here is an example attack to use as a starting point: http://zoobar.org/users.php?user=\%22\%3E\%3Cscript\%3Ealert\%28document.cookie\%29;\%3C/script\%3E