OpenCTI Project Links

• GitHub
• Documentation

System Requirements

I'll be running my VM with:

• 8 Cores
• 16 GiB RAM
• 128 GB disk

Creating the VM

Debian ISO

Installing Debian via the Internet

I'll be using the amd64 small ISO from the official Debian page. Create your VM using the hardware specifications above, or your own hardware specifications. Attach the .iso file and boot the VM.

VM Hardware

Installing the Operating System

Next, choose your language, location, and keyboard mapping.

Next, set a password for the root user.

Set a password for your non-root user.

Set your timezone.

Choose your country for the proper Debian package mirror. Then, choose your mirror. deb.debian.org should work in most cases.

1. Run the command su root and enter the 'root' user's password
2. Install sudo by running:

# Install operating system upgrades and install sudo
apt clean && apt update && apt upgrade -y && apt install -y sudo
# Add your non-root user to the sudo group
/usr/sbin/usermod -a -G sudo <username>
# Add the /usr/sbin directory to root's path at login
echo 'export PATH=/usr/sbin:$PATH' >> ~/.bashrc
# Exit out of your root session
exit

# Now running as your non-root user again
# Add the /usr/sbin directory to your non-root user's path at login
echo 'export PATH=/usr/sbin:$PATH' >> ~/.bashrc

3. Logoff from your non-root user's session and log back in
4. Now, verify your sudo privileges
   
   

Installing OpenCTI

The official documentation states that Docker is the recommended method to run the OpenCTI components, so that's what we'll be doing in this write-up.

Create an OpenCTI Service Account

sudo useradd -r -s /bin/bash -m -d /opt/opencti opencti_svc
sudo passwd opencti_svc

Increase Virtual Memory for ElasticSearch

sudo sysctl -w vm.max_map_count=1048575
echo 'vm.max_map_count=1048575' | sudo tee --append /etc/sysctl.conf

Install Docker Engine

Install Docker Engine on Debian

Instructions for installing Docker Engine on Debian

Docker Documentation

sudo apt install -y ca-certificates curl gnupg lsb-release
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/debian/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/debian $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo apt update && sudo apt install -y docker-ce docker-ce-cli containerd.io docker-compose-plugin docker-compose
sudo systemctl enable --now docker
sudo usermod -a -G docker opencti_svc

Log in as OpenCTI Service Account

Docker Compose File

When logging in as the opencti_svc user, you should be operating in /opt/opencti as the home directory. The first thing we'll do is grab the docker-compose.yml contents from this GitHub repository.

docker/docker-compose.yml at master · OpenCTI-Platform/docker

OpenCTI Docker deployment helpers. Contribute to OpenCTI-Platform/docker development by creating an account on GitHub.

GitHubOpenCTI-Platform

cd /opt/opencti
wget https://github.com/OpenCTI-Platform/docker/raw/master/docker-compose.yml -O docker-compose.yml

nano docker-compose.yml

Environment Variables

Generate some environment variables by running this command:

cat << EOF > .env
CONNECTOR_EXPORT_FILE_CSV_ID=$(cat /proc/sys/kernel/random/uuid)
CONNECTOR_EXPORT_FILE_STIX_ID=$(cat /proc/sys/kernel/random/uuid)
CONNECTOR_HISTORY_ID=$(cat /proc/sys/kernel/random/uuid)
CONNECTOR_IMPORT_FILE_STIX_ID=$(cat /proc/sys/kernel/random/uuid)
CONNECTOR_IMPORT_REPORT_ID=$(cat /proc/sys/kernel/random/uuid)
ELASTIC_MEMORY_SIZE=8G
MINIO_ROOT_PASSWORD=$(cat /proc/sys/kernel/random/uuid)
MINIO_ROOT_USER=$(cat /proc/sys/kernel/random/uuid)
OPENCTI_ADMIN_EMAIL=admin@opencti.io
OPENCTI_ADMIN_PASSWORD=CHANGEMEPLEASE
OPENCTI_ADMIN_TOKEN=$(cat /proc/sys/kernel/random/uuid)
OPENCTI_BASE_URL=http://localhost
RABBITMQ_DEFAULT_PASS=guest
RABBITMQ_DEFAULT_USER=guest
SMTP_HOSTNAME=$(hostname)
EOF

At this point you should have the following files in /opt/opencti

• docker-compose.yml
• .env

nano .env

• OPENCTI_ADMIN_EMAIL
  • Used to log into OpenCTI
  • Also, used for system and other alerts
• OPENCTI_ADMIN_PASSWORD
  • Password to log into OpenCTI
  • Change this and store in a password vault
• OPENCTI_BASE_URL
  • Change localhost to your FQDN or IP address
  • Example: http://10.148.148.3 or http://opencti.home.lab
• RABBITMQ_DEFAULT_USER
  • Change this and store in a password vault
• RABBITMQ_DEFAULT_PASS
  • Change this and store in a password vault

Launch the OpenCTI Stack

docker-compose up -d

To monitor any docker container logs after the stack is fully deployed, run the command docker-compose logs -f.

Logging into OpenCTI

In your web browser, navigate to http://ipaddress or http://fqdn. Remember, we configured the application to be served over TCP port 80, whereas most documentation references TCP port 8080.

The username and password were set by you in the .env variables file in OPENCTI_ADMIN_EMAIL and OPENCTI_ADMIN_PASSWORD respectively.

Upon first glance, the empty canvas on the OpenCTI UI can be a little underwhelming. OpenCTI does not ship with any data, so you either have to import it manually or use connectors to programmatically pull data.

Configuring OpenCTI Connectors

A list of officially supported connectors (and their configurations) is available on their GitHub repo.

GitHub - OpenCTI-Platform/connectors: OpenCTI Connectors

OpenCTI Connectors. Contribute to OpenCTI-Platform/connectors development by creating an account on GitHub.

GitHubOpenCTI-Platform

Connectors are divided into several categories:

• External Import
• Internal Enrichment
• Internal Export File
• Internal Import File
• Stream

Configure an External Import Connector

AlienVault OTX

For the sake of this walkthrough, let's configure the AlienVault OTX external connector, since this is a very powerful and widely used threat intel exchange.

Connector Roles and Permissions

According to the official documentation, the proper way to add connectors to OpenCTI is:

• Create a specific role for connectors
• Create an account per connector and attach the role to it

Create the Connector Account

We're still working in the Accesses tab from above.

Specify a password for the connector account and click Create.

Update the Account Roles

Click anywhere outside of the pane to return to the main view.

Update the Docker-Compose Configuration

We are going to use the docker-compose.yml template for the AlienVault connector directly from the project GitHub. We'll be borrowing a portion of this file and injecting into the main docker-compose.yml.

connectors/docker-compose.yml at master · OpenCTI-Platform/connectors

OpenCTI Connectors. Contribute to OpenCTI-Platform/connectors development by creating an account on GitHub.

GitHubOpenCTI-Platform

I'm going to copy and paste only the text highlighted in the screenshot:

cd /opt/opencti
nano docker-compose.yml

The screenshot below indicates how I copied and pasted the YAML syntax right above the redis and below the services keywords in the original file. I've also appended the following YAML syntax to the connector:

    depends_on:
      - opencti

This causes Docker Compose to pause initialization of the connector until the opencti container has been brought up. Add this to all of your connector YAML syntax.

      - OPENCTI_TOKEN=ChangeMe

      - OPENCTI_TOKEN=connector-api-token-here

      - CONNECTOR_ID=ChangeMe

Every connector must have a unique CONNECTOR_ID. There are UUID4 random generators on the web that you can use. Or, you can generate them in PowerShell or bash.

Bash: echo $(cat /proc/sys/kernel/random/uuid)

PowerShell: [Guid]::NewGuid().Guid

Then paste the output into the CONNECTOR_ID variable.

      - CONNECTOR_ID=random-uuid-v4-here

      - ALIENVAULT_API_KEY=ChangeMe

      - ALIENVAULT_API_KEY=alienvault-otx-api-key

You can now save the changes to your docker-compose.yml file. Once you've done that, you'll need to restart the OpenCTI stack by issuing these commands.

cd /opt/opencti
docker-compose down && docker-compose up -d

Again, you can watch the Docker container logs by running:

docker-compose logs -f

Exploring the Platform

In this tutorial, we got the platform installed and configured with a single external connector, the AlienVault connector. That is only scratching the surface in terms of available connectors and information you can import to the platform. Some other recommended external connectors to check out:

• abuse-ssl
• abuseipdb-ipblacklist
• cve
• mitre
• opencti (yes, that is the name of the connector)
• urlhaus

That is just to name a few. Remember the process generally follows these steps:

1. Take the docker-compose.yml contents from the connector on GitHub
2. Plug them into /opt/opencti/docker-compose.yml while being sure to maintain the indentation.

Upgrading OpenCTI

Make a Snapshot of Your VM

Log into Proxmox and click on your OpenCTI VM. Click on Snapshots > Take Snapshot. You could name it something like pre_upgrade_YYYYMMdd. You should see TASK OK in the output when the snapshot has been successfully created.

Update the OpenCTI Stack

cd /opt/opencti
docker-compose down && docker-compose pull && docker-compose up -d

Serving OpenCTI over TLS

Stop the OpenCTI Stack

cd /opt/opencti
docker-compose down

Create a Local Volume to Store TLS Cert and Key

nano docker-compose.yml

volumes:
  esdata:
  s3data:
  redisdata:
  amqpdata:
  opencti_https:

  opencti:
    image: opencti/platform:5.12.15
    environment:
      # ...
      # Removed by author for brevity
      # ...
    ports:
      - "80:8080"
    volumes:
      - opencti_https:/certs
    # ...
      # ...

Run these chained commands to start the stack and create the volume, then shut it down, so we can add our certificates there.

docker-compose up -d && docker-compose down

This will create the following path /var/lib/docker/volumes/opencti_opencti_https/_data/. Once created, place your .crt and .key TLS files in this directory, which will require root privileges.

Update the OpenCTI Stack

Update the Environment Variables

Let's say you got a TLS certificate for your OpenCTI instance with the hostname, opencti.domain.tld. This is the hostname we'll be referencing throughout this configuration example.

cd /opt/opencti
nano .env

OPENCTI_BASE_URL=http://opencti.home.lab

OPENCTI_BASE_URL=https://opencti.home.lab

Save your changes.

Update Docker Compose

Let's use sed to easily update the OPENCTI_URL variable in the docker-compose.yml file. The command below, will do the following.

• Backup the original docker-compose.yml to docker-compose.yml.bak
• Update the OPENCTI_URL variable with your https://opencti.domain.tld URL

sed -i.bak -e 's/OPENCTI_URL=http:\/\/opencti\:8080/OPENCTI_URL=https:\/\/opencti\.domain\.tld/g' docker-compose.yml

nano docker-compose.yml

  opencti:
    image: opencti/platform:5.12.15
    environment:
      # ...
      # ...
      # ...
      - APP__HTTPS_CERT__KEY=/certs/opencti.key
      - APP__HTTPS_CERT__CRT=/certs/opencti.crt
      #- APP__HTTPS_CERT__REJECT_UNAUTHORIZED=false
    ports:
      - "443:8080"

Effectively, what we're doing is this:

• Map /var/lib/docker/volumes/opencti_opencti_https/_data/opencti.key to /certs/opencti.key internally to the container
• Map /var/lib/docker/volumes/opencti_opencti_https/_data/opencti.crt to /certs/opencti.crt internally to the container
• Listen on TCP/443 — the default port for HTTP over TLS
• Uncomment APP__HTTPS_CERT__REJECT_UNAUTHORIZED if you're testing with a self-signed certificate that does not have a valid CA.

Bring up the Stack

docker-compose up -d

Once you've made all of the designated changes to the stack, it's time to update the stack with your changes. This will redploy the entire stack, so be patient while all of the changes are loaded and your containers are deployed.

Verify HTTPS Functionality

In your browser, try navigating to your new URL, https://opencti.domain.tld. You should find that your site loads normally and that your browser trusts the connection as evidenced by the padlock icon in the URL bar.

Also, make sure your containers are not reporting any issues with connecting to the API.

docker-compose logs -f

Inspect your worker and connector logs and ensure there are no error logs regarding API connectivity issues.

Conclusion

If you've followed along up to this point, I want to thank you for reading. I hope that this blog has helped you successfully get your OpenCTI instance running and configured. OpenCTI is a powerful cyber threat intelligence engine that can aggregate and enhance data from multiple sources. Check out their documentation for more ways to enhance your OpenCTI instance.