How to AutomateGoogle Cloud Security Audits with Terraform and Python

Security in cloud infrastructure is of utmost priority in today's cloud-driven world. GCP in itself is a powerful tool with its own set of functionalities but, like all its competitors, suffers from inconsistencies due to the scale and complexities of the cloud environment. Furthermore, security audits are highly necessary to identify any misconfigurations or vulnerabilities in the configuration, when done manually, these become pretty time-consuming and error-prone processes. \n \n Terraform and Python form a perfect combination for this automation of audits. Terraform is anIaaC - Infrastructure As A Code tool that allows declarative management of GCP resources while baking in security best practices. Python has extensive libraries and GCP API support for easy scripting on custom audit checks and automation workflows. We can integrate these tools to build a scalable, efficient, proactive security auditing system for GCP. \n \n The aim of this article is to show, programatically, with real-life examples and code snippets, how one could automate GCP security audits by using Terraform and Python. In this article, I will show you how to provision secured infrastructure and trigger automated security alerts in ways that will help with cloud security management.

Setting Up Your Environment

Before we provision any resources and create the required infrastructure for this article, we need to set up the Google Cloud environment. I will briefly explain and list the prerequisites, tools, and configurations needed in this section to get up and running.

Prerequisites

• An account on the Google Cloud Platform with administrative privileges.
• Basic knowledge of Google Cloud Platform services, Terraform, and Python.
• We would need Terraform and Python installed and running on your local machine or development environment.

Installing Required Tools

1. Install Terraform by downloading the Terraform binary from HashiCorp's official site. \n You can also follow the instructionshere for the other OS.

sudo apt-get update && sudo apt-get install -y gnupg software-properties-common wget -O- https://apt.releases.hashicorp.com/gpg | \ gpg --dearmor | \ sudo tee /usr/share/keyrings/hashicorp-archive-keyring.gpg > /dev/null sudo apt update sudo apt-get install terraform

2. Verify terraform installation:

terraform -version terraform -help terraform -help plan

3. We need Python 3.X installed. If not, download it from python.org. Use pip to install the required libraries:

pip install google-api-python-client google-auth terraform-validate Configuring Authentication and Permissions

To interact with Google Cloud, we need appropriate permissions and a service user account for automation. Follow these steps:

1. Create a Service Account

• Go to the Google Cloud Console.

• Navigate to IAM & Admin > Service Accounts > Create Service Account.

• Assign roles like Owner or Security Admin.

• Download the JSON key file and save it securely on your local machine.

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1. Authenticate Terraform

• Set up Terraform to use your service account credentials:

export GOOGLE_APPLICATION_CREDENTIALS="/path/to/where/you/stored/service-account-key.json"

• Add this to your .bashrc or .zshrc profile.

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1. Authenticate Python Scripts

   We need to configure the service account credentials in the Python script as well

from google.oauth2 import service_account from googleapiclient.discovery import build credentials = service_account.Credentials.from_service_account_file( "/path/to/where/you/stored/service-account-key.json" ) compute = build('compute', 'v1', credentials=credentials) print(" You have been Authenticated successfully! ") Provisioning Secure Infrastructure with Terraform

Terraform is an infrastructure as code tool that lets you build, change, and version infrastructure safely and efficiently by defining it as code. In the below section, I’ll walk you through creating secure infrastructure with Terraform.

Step 1: Creating a Terraform Configuration

Let’s begin by defining a secure Cloud Storage bucket, which will store all the user’s data. You can read more about Cloud Storage bucket here.

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1. Create a Terraform Configuration File:

   Save the following code in a file named main.tf

provider "google" { credentials = file(var.credentials_file) project = var.project_id region = var.region } resource "google_storage_bucket" "storage_bucket" { name = "storage-bucket-audit-${random_id.bucket_suffix.hex}" location = var.region force_destroy = false versioning { enabled = true } lifecycle_rule { action { type = "Delete" } condition { age = 365 } } uniform_bucket_level_access = true logging { log_bucket = var.logging_storage_bucket log_object_prefix = "storage-bucket-audit/" } } resource "random_id" "storage_bucket_suffix" { byte_length = 4 }

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2. Define Input Variables:

   Create a variables.tf file to hold configurable variables:

variable "credentials_file" { description = "service account JSON file" type = string } variable "project_id" { description = "Google Cloud project ID" type = string } variable "region" { description = "Google Cloud region" type = string default = "us-west1" } variable "logging_storage_bucket" { description = "Bucket to store access logs for the storage bucket" type = string }

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3. Add a Terraform State Backend (Optional)

   To ensure state management, configure a remote backend like Google Cloud Storage. This step is optional which avoids any conflict creating or updating the resources if you’re working in a team environment. Read this article on the terraform state conflicts.

terraform { backend "gcs" { bucket = "terraform-state-bucket" prefix = "terraform/state" } } Step 2: Applying the Configuration

1. Initialize Terraform by running the following command to download the necessary providers and modules

terraform init

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2. Validate the Configuration by ensuring the Terraform code has no syntax errors

terraform validate

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3. Apply the Configuration to provision the resources

terraform apply

\ Terraform will display the plan and prompt you for confirmation. Enter yes or y to proceed.

Step 3: Reviewing the Output

After applying the configuration, you’ll see outputs similar to:

google_storage_bucket.storage_bucket: Creation complete after 3s [id=storage-bucket-audit--xyz123]

\ Verify the bucket in the Google Cloud Console under Cloud Storage. It will have:

• Versioning is enabled and supports recovering deleted and overwritten objects.
• Logging enabled to track activities of access.
• Lifecycle policies that manage object retention.

Best Practices

• Use the least privileged IAM roles for your service accounts.
• Enable encryption at rest for all storage buckets.
• Audit sensitive information exposure in Terraform state files regularly.

Automating Security Audits with Python

While Terraform helps provision secure resources, Python handles it by automating security audits to ensure continuous compliance. In this section, I will explain and show how to use Python scripts to identify security misconfigurations in Google Cloud Platform.

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Step 1: Setting Up Python

1. Install Required Libraries

   Ensure the necessary Python libraries are installed:

pip install google-api-python-client google-auth

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2. Authenticate Using Service Account

   Use the service account credentials to interact with GCP APIs:

from google.oauth2 import service_account from googleapiclient.discovery import build # Path to your service account key file SERVICE_ACCOUNT_FILE = '/path/to/where/you/stored/service-account-key.json' # Authenticate credentials = service_account.Credentials.from_service_account_file(SERVICE_ACCOUNT_FILE) storage_client = build('storage', 'v1', credentials=credentials) print(" You have been Authenticated successfully! ") Step 2: Writing a Security Audit Script in Python

1. Audit IAM Policies for Overly Permissive Roles:

   This script identifies Cloud Storage buckets with overly permissive IAM policies, such as granting "allUsers" or "allAuthenticatedUsers" access:

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from googleapiclient.discovery import build from googleapiclient.errors import HttpError def list_buckets_with_overly_permissions(project_id): # Initialize the storage client storage_client = build('storage', 'v1') try: # List all the buckets that are in the project storage_buckets = storage_client.buckets().list(project=project_id).execute() while storage_buckets: for bucket in storage_buckets.get('items', []): bucket_name = bucket['name'] try: # fetch the IAM policy for the selected bucket iam_policy = storage_client.buckets().getIamPolicy(bucket=bucket_name).execute() for binding in iam_policy.get('bindings', []): members = binding.get('members', []) if 'allUsers' in members or 'allAuthenticatedUsers' in members: print(f"Bucket '{bucket_name}' has overly permissive IAM policy: {binding}") except HttpError as e: print(f" Failed: fetching IAM policy for the bucket '{bucket_name}': {e} ") # If the project has multiple buckets, this block will handle the pagination next_page_token = storage_buckets.get('nextPageToken') if next_page_token: storage_buckets = storage_client.buckets().list(project=project_id, pageToken=next_page_token).execute() else: storage_buckets = None except HttpError as e: print(f"Could not list the buckets due to : {e}") # How To Use project_id = 'replace-your-project-id' list_buckets_with_overly_permissions(project_id)

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2. Check for Missing Logging Configurations:

   This snippet verifies if access logging is enabled for Cloud Storage buckets or not

from googleapiclient.discovery import build from googleapiclient.errors import HttpError def check_bucket_logging(project_id): # Initialize the storage client storage_client = build('storage', 'v1') try: # List all the buckets that are in the project storage_buckets = storage_client.buckets().list(project=project_id).execute() while storage_buckets: for bucket in storage_buckets.get('items', []): bucket_name = bucket['name'] try: # Fetch the bucket details bucket_info = storage_client.buckets().get(bucket=bucket_name).execute() # Check if logging is enabled or not if 'logging' not in bucket_info: print(f"Bucket '{bucket_name}' does not have logging enabled.") else: logging_config = bucket_info['logging'] print(f"Bucket '{bucket_name}' has logging enabled: {logging_config}") except HttpError as e: print(f" Could not fetch the details for bucket '{bucket_name}': {e}") # If the project has multiple buckets, this block will handle the pagination next_page_token = storage_buckets.get('nextPageToken') if next_page_token: storage_buckets = storage_client.buckets().list(project=project_id, pageToken=next_page_token).execute() else: storage_buckets = None except HttpError as e: print(f"Error listing buckets: {e}") # How To Use project_id = 'replace-your-project-id' check_bucket_logging(project_id) Step 3: How to Run the Python Script

Execute the Python script using the below command:

python perform_gcp_audit.py

The output of the above script will print the buckets with oepn IAM roles or missing logging configurations, asking you to take the required actions.

Step 4: Automating the Process

To continuously run the above script, we can schedule the script using cron or can integrate it with a CI/CD pipeline.

Example of a cron job to run the script daily:

0 0 * * * /usr/bin/python3 /path/to/perform_gcp_audit.py Best Practices

• Log audit results to a secure location for traceability.
• Combine findings with GCP’s Security Command Center for a holistic security view.
• Regularly update the script to include checks for new services or configurations.

Combining Python and Terraform to Automate the Audits

We will combine Python and Terraform to create an automated workflow for provisioning infrastructure and automating performing the Securtity Audits. I will walk through on how to integrate Python and Terraform to build a proactive security system.

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Step 1: Need to Export Terraform Outputs for Python Scripts

Terraform allows to export information about the resources it creates. These outputs can be ingested by Python scripts for security audits.

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1. Specify Outputs in Terraform by adding an outputs.tf file to your Terraform configuration:

output "list_buckets" { value = [for bucket in google_storage_bucket.secure_bucket : bucket.name] }

This exports the names of all storage buckets created by Terraform.

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2. Apply the Terraform Configuration by running the following commands to update and retrieve the outputs:

terraform apply terraform output -json > terraform_output.json Step 2: Consuming Terraform Outputs in Python

Use the Terraform outputs to audit only the resources provisioned by Terraform which makes the audit more targeted.

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1. Load Terraform Outputs in Python

import json # Load Terraform outputs with open('terraform_output.json') as file: terraform_outputs = json.load(file) bucket_names = terraform_outputs['bucket_names']['value'] print("List of the Buckets to audit: {bucket_names}")

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2. Integrate Outputs with Audit Scripts

   Modify the previous IAM audit script to use these bucket names:

def audit_buckets_with_outputs(storage_client, bucket_names): for bucket_name in bucket_names: iam_policy = storage_client.buckets().getIamPolicy(bucket=bucket_name).execute() for binding in iam_policy.get('bindings', []): if 'allUsers' in binding['members'] or 'allAuthenticatedUsers' in binding['members']: print(f"Bucket {bucket_name} has weak permissions: {binding}") audit_buckets_with_outputs(storage_client, bucket_names) Step 3: Automating the Workflow

To create a fully automated workflow, we need to create a CI/CD pipeline and integrate Terraform resources provisioning and Python auditing scripts in it.

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1. Create a Shell Script to Orchestrate the Process

#!/bin/bash # Step 1 will Provision the infrastructure with Terraform terraform apply -auto-approve # Step 2 will Export the Terraform outputs terraform output -json > terraform_output.json # Step 3 will Run the Python security audit script python perform_gcp_audit.py

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2. Integrate with CI/CD using tools like GitHub Actions or Google Cloud Build to automate the script.

   Below is the example of GitHub Actions configuration:

name: Terraform + Python Security Audit on: push: branches: - main jobs: build: runs-on: ubuntu-latest steps: - name: Checkout code uses: actions/checkout@v2 - name: Set up Python uses: actions/setup-python@v2 with: python-version: 3.x - name: Install the required dependencies run: pip install google-api-python-client google-auth - name: Set up and install Terraform uses: hashicorp/setup-terraform@v2 with: terraform_version: 1.5.7 - name: Run automation script run: ./run_audit.sh Step 4: Enhancing with Alerts and Reporting

Add notifications for audit results:

1. Python script to send emails for critical findings:

import smtplib from email.mime.text import MIMEText def send_alerts_for_findings(alert_message): msg = MIMEText(alert_message) msg['Subject'] = 'Security Audit Alert from GCP' msg['From'] = '[email protected]' msg['To'] = '[email protected]' with smtplib.SMTP('smtp.example.com', 587) as server: server.starttls() server.login('[email protected]', 'your-password') server.send_message(msg) send_alerts_for_findings("Bucket 'sample-storage-bucket' has weak permissions.")

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2. We can use monitoring platforms like Google Cloud Monitoring or Wavefront for visualizing these Audit Results.

Best Practices

• Should use CI/CD pipelines to implement security checks after every infrastructure change.
• Shoulds regularly update Terraform configurations and Python scripts to align with the latest security standards and patches.
• Should store Terraform state files and Python logs securely in the Cloud Storage Buckets.

Real-World Use Case: Securing a Web Application on GCP

We implemented some pieces of the puzzle above. Now let’s explore a real-world scenario where Terraform and Python automate security for a web application hosted on Google Cloud Platform. I will walk you through the scenario of how you would provision secure resources, audit the resources, and introduce proactive monitoring workflows.

Scenario Overview

A company hosts their e-commerce website on the Google Cloud Platform using:

• A Compute VM instance for the application server.
• A Cloud SQL VM for the database.
• A Cloud Storage bucket for data uploaded by users.

\ Our goal is to:

1. Provision these above-mentioned resources securely using Terraform.
2. Audit the common security issues using Python in the above infrastructure we created.
3. Monitor the infrastructure in real time and trigger an alert on any misconfiguration found.

Step 1: Use Terraform to Provision the Infrastructure

1. Terraform Configuration:

   Here’s how the infrastructure is defined in main.tf

# Create the Compute VM resource "google_compute_instance" "app_server" { name = "secure-app-server" machine_type = "e2-medium" zone = "us-west1-a" # Specify Boot Disk boot_disk { initialize_params { image = "debian-cloud/debian-11" # Use an OS image with long-term support } } # Configure Network Interface network_interface { network = "default" # Allow external connectivity through NAT access_config {} } # Secure Metadata metadata = { enable-oslogin = "TRUE" # Enforce OS Login for secure access } # Add Secure Firewall Tags tags = ["app", "audit", "secure"] } # Create the Cloud SQL Database Instance resource "google_sql_database_instance" "cloud-sql-server" { name = "secure-db-server" database_version = "MYSQL_8_0" region = "us-west1" # Database Settings settings { tier = "db-f1-micro" # Low-cost instance type for testing/small workloads backup_configuration { enabled = true # Enable automatic backups } ip_configuration { ipv4_enabled = false # Disable public IP access private_network = "default" # Use private networking for secure connectivity } availability_type = "ZONAL" # Choose regional for higher availability if needed } } # Storage Bucket for Uploads resource "google_storage_bucket" "storage-bucket" { name = "storage-bucket-uploads-${random_id.bucket_suffix.hex}" location = "US" uniform_bucket_level_access = true # Enforce uniform ACL for better security # Enable Versioning to prevent accidental deletions versioning { enabled = true } # Secure Bucket Settings lifecycle_rule { action { type = "Delete" } condition { age = 90 # Delete objects older than 90 days to manage storage costs } } logging { log_bucket = "advait-patel-log-bucket-name" # Add logging to a monitoring bucket log_object_prefix = "logs/" } } # Generate Random Suffix for Unique Bucket Names resource "random_id" "bucket_suffix" { byte_length = 4 }

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2. Apply the Configuration

terraform init terraform apply -auto-approve Step 2: Auditing the Infrastructure

1. Auditing IAM Roles for Compute Engine

   Check if any instance has overly permissive IAM roles:

from googleapiclient.discovery import build from googleapiclient.errors import HttpError def perform_audit_compute_instance_iam(project_id, zones): """ This code Audits Google Compute Engine instances for overly permissive IAM roles within the given Project. """ # this will initialize the compute client compute_client = build('compute', 'v1') for each_zone in zones: print(f" Checking the instances in the given zone: {each_zone} ") try: # List instances in the given zone list_instances = compute_client.instances().list(project=project_id, zone=each_zone).execute() for list_instances in list_instances.get('items', []): instance_name = instance['name'] try: # Fetch IAM policy for the given instance iam_policy = compute_client.instances().getIamPolicy( project=project_id, zone=each_zone, resource=instance_name ).execute() # Now Validate the overly permissive IAM permissions for binding in iam_policy.get('bindings', []): members = binding.get('members', []) if 'allUsers' in members or 'allAuthenticatedUsers' in members: print(f"Instance '{instance_name}' in zone '{each_zone}' has overly permissive IAM permissions: {binding}") except HttpError as e: print(f"Could not fetch the IAM policy for instance '{instance_name}' in zone '{each_zone}': {e}") except HttpError as e: print(f"Error listing instances in zone '{each_zone}': {e}") # How to Use project_id = 'replace-your-project-id' zones = ['us-west1-a', 'us-west1-b', 'us-west1-c'] perform_audit_compute_instance_iam(project_id, zones)

\ Example Output

Checking instances in zone: us-west1-a Instance 'advait-patel-1' in zone 'us-west1-a' has overly permissive IAM permissions: {'role': 'roles/compute.viewer', 'members': ['allUsers']} Checking instances in zone: us-west1-b Could not find the overly permissive IAM permissions. ...

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2. Auditing SQL Instance SSL Settings:

   Verify if SSL connections are enforced for the Cloud SQL instance or not

from googleapiclient.discovery import build from googleapiclient.errors import HttpError def perform_sql_instance_ssl_audit(project_id, credentials): """ Validate if the SSL connections are enforced for all the available Cloud SQL instances in a project or not. """ # this will initialize the SQL Admin client sql_client = build('sqladmin', 'v1', credentials=credentials) try: # Print all the Cloud SQL instances in the given project list_instances = sql_client.instances().list(project=project_id).execute() if 'items' not in list_instances or not list_instances['items']: print(f" Could not find Cloud SQL instances in the project '{project_id}'.") return # Iterate over each instance to check SSL settings for instance in list_instances['items']: instance_name = instance['name'] require_ssl = instance.get('settings', {}).get('ipConfiguration', {}).get('requireSsl', False) if require_ssl: print(f"SQL Instance '{instance_name}' enforces SSL connections.") else: print(f"WARNING: SQL Instance '{instance_name}' does NOT enforce SSL connections.") except HttpError as e: print(f"Could not retrieve Cloud SQL instances: {e}") # How To Use project_id = 'replace-your-project-id' credentials = None # Replace with your Google Cloud credentials object perform_sql_instance_ssl_audit(project_id, credentials)

\ Example Output

SQL Instance 'advait-test' enforces SSL connections. WARNING: SQL Instance 'advait-patel-test' does NOT enforce SSL connections. Could not find Cloud SQL instances in the project 'replace-your-project-id'. Step 3: Continuous Monitoring and Alerts

1. Setup Monitoring for GCP Resources: Use Google Cloud Monitoring to set up alerts for critical configurations:

• Log-Based Alerts: Monitor IAM changes for Compute Engine and Storage buckets.

• Uptime Checks: Ensure the web server is accessible.

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1. Schedule Automated Security Audits: Combine Terraform and Python into a cron job or CI/CD pipeline to ensure regular security checks:

0 3 * * * /usr/bin/python3 /path/to/perform_security_audit.py

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3. Email Alerts for Misconfigurations: Send alerts for critical issues detected during audits:

import smtplib from email.mime.text import MIMEText from email.mime.multipart import MIMEMultipart def send_alert_email_for_misconfig(misconfig_details, recipient_email, sender_email, smtp_server, smtp_port, smtp_password): try: # Create an email content subject = "Critical Alert from SRE Team: Issue Detected During Performing Audit" body = f""" We found a critical issue while performing the recent audit: {misconfig_details} """ # Set up the email client msg = MIMEMultipart() msg['From'] = sender_email msg['To'] = recipient_email msg['Subject'] = subject # Attach the email body msg.attach(MIMEText(body, 'plain')) # Connect to the SMTP server and send the email with smtplib.SMTP(smtp_server, smtp_port) as server: server.starttls() # Secure the connection server.login(sender_email, smtp_password) server.sendmail(sender_email, recipient_email, msg.as_string()) print(f"Success: An Alert email is successfully sent to {recipient_email}.") except Exception as e: print(f"Could not send an alert email due to: {e}") # How To Use misconfig_details = "Found A Critical misconfiguration Compute Virtual Machine!" recipient_email = "[email protected]" sender_email = "[email protected]" smtp_server = "smtp.gmail.com" smtp_port = 587 smtp_password = "replace-your-smtp-password" send_alert_email_for_misconfig(misconfig_details, recipient_email, sender_email, smtp_server, smtp_port, smtp_password) Step 4: Validating the Workflow

1. Deploy the infrastructure using Terraform.
2. Run the Python audit script to check for security issues.
3. Fix identified issues (e.g., enable SSL for Cloud SQL, correct IAM permissions).
4. Test monitoring and alerting to ensure quick response to future issues.

Conclusion

In this article, we looked at how to automate security audits of Google Cloud using Terraform and Python. By combining the powers of both, you will end up with a solid proactive security workflow.

Key takeaways include: \n \n ==Infrastructure as a Code-IaaC for Secure Deployments==: Terraform simplifies the resource provisioning process while maintaining security best practices, including IAM role restrictions and bucket-level access controls. \n \n ==Python for Continuous Audits==: Python scripts can be easily integrated with GCP APIs to run automated security checks, such as the detection of misconfigured IAM policies, enabling logging, and enforcing SSL connections. \n \n ==Integration for Scalability==: Terraform with Python sets up a powerful pipeline not limited to resource provisioning and auditing but includes continuous monitoring of resources as well. Therefore, this is the end-to-end security solution. \n \n ==Real-World Application==: The tools were applied to a real-world use case, where it showed how an e-commerce application can be secured, practical workflows and coding examples were shown for CI/CD integrations to attain continuous compliance. That said, this approach is highly scalable and adaptable for any kind of cloud environment, making sure that as growth happens, the security of your infrastructure is maintained. More importantly, integrating these workflows with monitoring and alerting systems allows teams to quickly respond to security and, hence minimize risks.