How to Setup a Cowrie SSH Honeypot

Cowrie is a medium interaction SSH and Telnet honeypot, which can log brute force attacks and an attacker's shell interaction. Cowrie is an excellent project developed by Michel Oosterhof.

This post provides instructions on how to configure a Cowrie SSH honeypot on an Ubuntu 16.04 system. I recommend that you configure Cowrie on a cloud server instance rather than a host on your home network.

I will publish another post soon to show how to visualize the attacker's activity in Splunk.

Change the Port You Will Use to Administer the Server

Cowrie will be listening for SSH connections on port 22. You'll want to configure the SSH service to listen on a different port for you to connect to and administer the server.

sudo vi /etc/ssh/sshd_config

Under "# What ports, IPs and protocols we listen for", change the port number to 3393 or your preferred port number.

Write your changes and quit vi.

Ctrl + C

:wq

Restart the SSH service.

service ssh restart

By running the command below, you can see that the server is now listening for connections on port 3393.

netstat -tan
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp0      0 0.0.0.0:3393            0.0.0.0:*               LISTEN

Install and Configure Cowrie

Download updated package lists.

sudo apt-get update

Install Cowrie's dependencies.

sudo apt-get install python2.7 git virtualenv libmpfr-dev libssl-dev libmpc-dev libffi-dev build-essential libpython-dev python-pip

Add a new user named, cowrie.

sudo adduser --disabled-password cowrie

Switch to the new user, cowrie

sudo su - cowrie

Navigate to the home directory of user, cowrie, and clone the cowrie git repository.

git clone https://github.com/micheloosterhof/cowrie.git

Create a new virtual environment for cowrie.

cd cowrie

virtualenv cowrie-env

Activate the virtual environment.

source cowrie-env/bin/activate

The terminal will display "(cowrie-env)" before the username, cowrie.

Install pycrypto, Crypto and other requirements.

pip install pycrypto Crypto

(cowrie-env)$ pip install -r requirements.txt

Generate a DSA key for the cowrie instance.

cd data

ssh-keygen -t dsa -b 1024 -f ssh_host_dsa_key

cd ..

export PYTHONPATH=/home/cowrie/cowrie

Additional Cowrie Configuration

Make a copy of the config file for your new cowrie instance.

cd /home/cowrie/cowrie/

cp cowrie.cfg.dist cowrie.cfg

vi ./cowrie.cfg

Set the hostname in the configuration file to a server name of your choice. E.g. "fileserver4"

Change the "Port to listen for incoming SSH connections" to port 22.

Write your changes and quit vi.

Ctrl + C

:wq

Enable authbind in cowrie's start.sh file.

sudo vi /home/cowrie/cowrie/start.sh

Change line 2 to read:

AUTHBIND_ENABLED=yes

sudo apt-get install authbind

sudo touch /etc/authbind/byport/22
sudo chown cowrie /etc/authbind/byport/22
sudo chmod 777 /etc/authbind/byport/22

Start Cowrie

Execute the following commands to start Cowrie.

sudo su cowrie

cd /home/cowrie/cowrie/

source cowrie-env/bin/activate

./start.sh

Verify cowrie is listening on port 22 by running the command below.

netstat -tan

Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN

Execute the following command to stop Cowrie.

./stop.sh

How to Stop and Start the SSH Service (Running on the Custom Port You Chose Earlier)

If your server is accessible via a console in your cloud provider's management console, you may want to disable the SSH service on your server and enable it only when you need to establish a SSH connection to administer it.

This will prevent SSH brute force attacks against the listening service.

Execute the following command to stop the SSH service.

sudo /etc/init.d/ssh stop

Validate that the server is no longer listening on the custom SSH port. You should see that Cowrie is still listening on port 22.

netstat -tan

Execute the following command to start the SSH service.

sudo /etc/init.d/ssh start

Test Connectivity to the Cowrie Honeypot

Connect to your server on port 22, enter any password and you will be authenticated successfully.

Execute some commands for Cowrie to log.

Review the Cowrie Log File

Connect to your server (not the Cowrie instance) and review the log file.

cat /home/cowrie/cowrie/log/cowrie.log | less

The attacker's IP address will be shown in the red areas in the image below.

I will be writing a post soon on how to visualize the attacks against your honeypot using Splunk.