Collect Proofpoint Web Browser Isolation logs

Supported in:

Google secops SIEM

This document explains how to ingest Proofpoint Web Browser Isolation logs to Google Security Operations using Google Cloud Storage V2.

Proofpoint Web Browser Isolation is a remote browser isolation service that protects users from web-based threats by rendering web content in a secure cloud environment, preventing malicious code from reaching the endpoint. It provides browsing activity logs through the Proofpoint TAP SIEM API. The parser extracts fields from isolation event data and maps them to the Unified Data Model (UDM), capturing URL classifications, user actions, security dispositions, and browsing session metadata.

Before you begin

Make sure you have the following prerequisites:

A Google SecOps instance
A GCP project with Cloud Storage API enabled
Permissions to create and manage GCS buckets
Permissions to manage IAM policies on GCS buckets
Permissions to create Cloud Run services, Pub/Sub topics, and Cloud Scheduler jobs
Privileged access to Proofpoint with TAP SIEM API credentials (Service Principal and API Secret)

Create Google Cloud Storage bucket

Go to the Google Cloud Console.
Select your project or create a new one.
In the navigation menu, go to Cloud Storage > Buckets.
Click Create bucket.

Provide the following configuration details:

Setting	Value
Name your bucket	Enter a globally unique name (for example, `proofpoint-wbi-logs`)
Location type	Choose based on your needs (Region, Dual-region, Multi-region)
Location	Select the location (for example, `us-central1`)
Storage class	Standard (recommended for frequently accessed logs)
Access control	Uniform (recommended)
Protection tools	Optional: Enable object versioning or retention policy

Click Create.

Collect Proofpoint TAP SIEM API credentials

Obtain API credentials

Sign in to the Proofpoint TAP dashboard.
Navigate to Settings > Connected Applications.
Click Create New Credential (or use an existing SIEM API credential).
Copy and securely store the following credentials:
- Service Principal: Copy this value
- API Secret: Copy this value
Note: The TAP SIEM API uses HTTP Basic authentication with the Service Principal as the username and the API Secret as the password. Contact Proofpoint support to confirm that browser isolation events are included in your subscription tier.

Verify permissions

To verify the API credentials have the required permissions:

Sign in to the Proofpoint TAP dashboard.
Navigate to Settings > Connected Applications.
Confirm the credential is listed and has an Active status.
Verify the credential has SIEM API access enabled.

Test API access

Test your credentials before proceeding with the integration:

# Replace with your actual credentials
SERVICE_PRINCIPAL="<your-service-principal>"
API_SECRET="<your-api-secret>"

# Test TAP SIEM API access - fetch events from last hour
curl -v -u "${SERVICE_PRINCIPAL}:${API_SECRET}" \
  "https://tap-api-v2.proofpoint.com/v2/siem/all?format=json&sinceSeconds=3600"

Create a service account for the Cloud Run function

The Cloud Run function needs a service account with permissions to write to GCS bucket and be invoked by Pub/Sub.

Create service account

In the GCP Console, go to IAM & Admin > Service Accounts.
Click Create Service Account.
Provide the following configuration details:
- Service account name: Enter proofpoint-wbi-collector-sa
- Service account description: Enter Service account for Cloud Run function to collect Proofpoint Web Browser Isolation logs
Click Create and Continue.
In the Grant this service account access to project section, add the following roles:
1. Click Select a role.
2. Search for and select Storage Object Admin.
3. Click + Add another role.
4. Search for and select Cloud Run Invoker.
5. Click + Add another role.
6. Search for and select Cloud Functions Invoker.
Click Continue.
Click Done.

These roles are required for:

Storage Object Admin: Write logs to GCS bucket and manage state files
Cloud Run Invoker: Allow Pub/Sub to invoke the function
Cloud Functions Invoker: Allow function invocation

Grant IAM permissions on GCS bucket

Grant the service account write permissions on the GCS bucket:

Go to Cloud Storage > Buckets.
Click on your bucket name (for example, proofpoint-wbi-logs).
Go to the Permissions tab.
Click Grant access.
Provide the following configuration details:
- Add principals: Enter the service account email (for example, proofpoint-wbi-collector-sa@PROJECT_ID.iam.gserviceaccount.com)
- Assign roles: Select Storage Object Admin
Click Save.

Create a Pub/Sub topic

Create a Pub/Sub topic that Cloud Scheduler will publish to and the Cloud Run function will subscribe to.

In the GCP Console, go to Pub/Sub > Topics.
Click Create topic.
Provide the following configuration details:
- Topic ID: Enter proofpoint-wbi-trigger
- Leave other settings as default
Click Create.

Create a Cloud Run function to collect logs

The Cloud Run function will be triggered by Pub/Sub messages from Cloud Scheduler to fetch browser isolation events from the Proofpoint TAP SIEM API and write them to GCS.

In the GCP Console, go to Cloud Run.
Click Create service.
Select Function (use an inline editor to create a function).
In the Configure section, provide the following configuration details:

Setting Value

Service name proofpoint-wbi-collector

Region Select region matching your GCS bucket (for example, us-central1)

Runtime Select Python 3.12 or later
In the Trigger (optional) section:
1. Click + Add trigger.
2. Select Cloud Pub/Sub.
3. In Select a Cloud Pub/Sub topic, choose the Pub/Sub topic (proofpoint-wbi-trigger).
4. Click Save.
In the Authentication section:
1. Select Require authentication.
2. Check Identity and Access Management (IAM).
Note: Pub/Sub will automatically handle authentication when invoking the function.
Scroll down and expand Containers, Networking, Security.
Go to the Security tab:
- Service account: Select the service account (proofpoint-wbi-collector-sa)

Setting	Value
Service name	`proofpoint-wbi-collector`
Region	Select region matching your GCS bucket (for example, `us-central1`)
Runtime	Select Python 3.12 or later

Go to the Containers tab:

Click Variables & Secrets.
Click + Add variable for each environment variable:

Variable Name	Example Value	Description
`GCS_BUCKET`	`proofpoint-wbi-logs`	GCS bucket name
`GCS_PREFIX`	`wbi-logs`	Prefix for log files
`STATE_KEY`	`wbi-logs/state.json`	State file path
`SERVICE_PRINCIPAL`	`your-service-principal`	Proofpoint TAP Service Principal
`API_SECRET`	`your-api-secret`	Proofpoint TAP API Secret
`LOOKBACK_SECONDS`	`3600`	Lookback period in seconds (default: 1 hour)

In the Variables & Secrets section, scroll down to Requests:
- Request timeout: Enter 600 seconds (10 minutes)
Go to the Settings tab:
- In the Resources section:
  - Memory: Select 512 MiB or higher
  - CPU: Select 1
In the Revision scaling section:
- Minimum number of instances: Enter 0
- Maximum number of instances: Enter 100 (or adjust based on expected load)
Click Create.
Wait for the service to be created (1-2 minutes).
After the service is created, the inline code editor will open automatically.

Add function code

Enter main in the Entry point field.

In the inline code editor, create two files:

First file - main.py:

import functions_framework
from google.cloud import storage
import json
import os
import urllib3
from datetime import datetime, timezone, timedelta
import time
import base64

# Initialize HTTP client with timeouts
http = urllib3.PoolManager(
  timeout=urllib3.Timeout(connect=5.0, read=60.0),
  retries=False,
)

# Initialize Storage client
storage_client = storage.Client()

# Environment variables
GCS_BUCKET = os.environ.get('GCS_BUCKET')
GCS_PREFIX = os.environ.get('GCS_PREFIX', 'wbi-logs')
STATE_KEY = os.environ.get('STATE_KEY', 'wbi-logs/state.json')
SERVICE_PRINCIPAL = os.environ.get('SERVICE_PRINCIPAL')
API_SECRET = os.environ.get('API_SECRET')
LOOKBACK_SECONDS = int(os.environ.get('LOOKBACK_SECONDS', '3600'))

TAP_API_BASE = "https://tap-api-v2.proofpoint.com/v2/siem"

def parse_datetime(value: str) -> datetime:
  """Parse ISO datetime string to datetime object."""
  if value.endswith("Z"):
    value = value[:-1] + "+00:00"
  return datetime.fromisoformat(value)

@functions_framework.cloud_event
def main(cloud_event):
  """
  Cloud Run function triggered by Pub/Sub to fetch Proofpoint
  Web Browser Isolation events via TAP SIEM API and write to GCS.

  Args:
    cloud_event: CloudEvent object containing Pub/Sub message
  """

  if not all([GCS_BUCKET, SERVICE_PRINCIPAL, API_SECRET]):
    print('Error: Missing required environment variables')
    return

  try:
    # Get GCS bucket
    bucket = storage_client.bucket(GCS_BUCKET)

    # Load state
    state = load_state(bucket, STATE_KEY)

    now = datetime.now(timezone.utc)

    # Determine since_seconds from state
    since_seconds = LOOKBACK_SECONDS
    if isinstance(state, dict) and state.get("last_event_time"):
      try:
        last_time = parse_datetime(state["last_event_time"])
        elapsed = (now - last_time).total_seconds()
        # Add 120 seconds overlap to catch delayed events
        since_seconds = int(elapsed) + 120
        # TAP API maximum is 1 hour (3600 seconds)
        since_seconds = min(since_seconds, 3600)
      except Exception as e:
        print(f"Warning: Could not parse last_event_time: {e}")

    print(f"Fetching events from last {since_seconds} seconds")

    # Build auth header (Basic auth)
    auth_string = f"{SERVICE_PRINCIPAL}:{API_SECRET}"
    auth_bytes = auth_string.encode('utf-8')
    auth_b64 = base64.b64encode(auth_bytes).decode('utf-8')

    # Fetch all SIEM events
    records = fetch_siem_events(
      auth_b64=auth_b64,
      since_seconds=since_seconds,
    )

    if not records:
      print("No new events found.")
      save_state(bucket, STATE_KEY, now.isoformat())
      return

    # Write to GCS as NDJSON
    timestamp = now.strftime('%Y%m%d_%H%M%S')
    object_key = f"{GCS_PREFIX}/logs_{timestamp}.ndjson"
    blob = bucket.blob(object_key)

    ndjson = '\n'.join([json.dumps(record, ensure_ascii=False) for record in records]) + '\n'
    blob.upload_from_string(ndjson, content_type='application/x-ndjson')

    print(f"Wrote {len(records)} records to gs://{GCS_BUCKET}/{object_key}")

    # Update state
    save_state(bucket, STATE_KEY, now.isoformat())

    print(f"Successfully processed {len(records)} records")

  except Exception as e:
    print(f'Error processing logs: {str(e)}')
    raise

def load_state(bucket, key):
  """Load state from GCS."""
  try:
    blob = bucket.blob(key)
    if blob.exists():
      state_data = blob.download_as_text()
      return json.loads(state_data)
  except Exception as e:
    print(f"Warning: Could not load state: {e}")

  return {}

def save_state(bucket, key, last_event_time_iso: str):
  """Save the last event timestamp to GCS state file."""
  try:
    state = {'last_event_time': last_event_time_iso}
    blob = bucket.blob(key)
    blob.upload_from_string(
      json.dumps(state, indent=2),
      content_type='application/json'
    )
    print(f"Saved state: last_event_time={last_event_time_iso}")
  except Exception as e:
    print(f"Warning: Could not save state: {e}")

def fetch_siem_events(auth_b64: str, since_seconds: int):
  """
  Fetch events from the Proofpoint TAP SIEM API.

  The TAP SIEM API returns all event types (clicks, messages, isolation)
  in a single response. The sinceSeconds parameter controls the lookback window
  (maximum 3600 seconds / 1 hour).

  Args:
    auth_b64: Base64-encoded Service Principal:API Secret for Basic auth
    since_seconds: Fetch events from the last N seconds (max 3600)

  Returns:
    List of event records
  """
  headers = {
    'Authorization': f'Basic {auth_b64}',
    'Accept': 'application/json',
    'User-Agent': 'GoogleSecOps-ProofpointWBICollector/1.0',
  }

  url = f"{TAP_API_BASE}/all?format=json&sinceSeconds={since_seconds}"
  backoff = 1.0
  max_retries = 3

  for attempt in range(max_retries):
    try:
      response = http.request('GET', url, headers=headers)

      # Handle rate limiting with exponential backoff
      if response.status == 429:
        retry_after = int(response.headers.get('Retry-After', str(int(backoff))))
        print(f"Rate limited (429). Retrying after {retry_after}s...")
        time.sleep(retry_after)
        backoff = min(backoff * 2, 30.0)
        continue

      if response.status != 200:
        print(f"HTTP Error: {response.status}")
        response_text = response.data.decode('utf-8')
        print(f"Response body: {response_text}")
        return []

      data = json.loads(response.data.decode('utf-8'))

      # TAP SIEM API returns events grouped by type
      all_events = []

      # Collect all event types
      for key in ['clicksPermitted', 'clicksBlocked', 'messagesDelivered', 'messagesBlocked']:
        events = data.get(key, [])
        if events:
          for event in events:
            event['_tap_event_type'] = key
          all_events.extend(events)
          print(f"Retrieved {len(events)} {key} events")

      print(f"Total events retrieved: {len(all_events)}")
      return all_events

    except Exception as e:
      print(f"Error fetching SIEM events (attempt {attempt + 1}): {e}")
      if attempt < max_retries - 1:
        time.sleep(backoff)
        backoff = min(backoff * 2, 30.0)

  return []

Second file - requirements.txt:

functions-framework==3.*
google-cloud-storage==2.*
urllib3>=2.0.0

Click Deploy to save and deploy the function.
Wait for deployment to complete (2-3 minutes).

Note: The Pub/Sub trigger configuration automatically creates the necessary subscriptions and permissions.

Create Cloud Scheduler job

Cloud Scheduler will publish messages to the Pub/Sub topic at regular intervals, triggering the Cloud Run function.

In the GCP Console, go to Cloud Scheduler.
Click Create Job.

Provide the following configuration details:

Setting	Value
Name	`proofpoint-wbi-collector-hourly`
Region	Select same region as Cloud Run function
Frequency	`0 * * * *` (every hour, on the hour)
Timezone	Select timezone (UTC recommended)
Target type	Pub/Sub
Topic	Select the Pub/Sub topic (`proofpoint-wbi-trigger`)
Message body	`{}` (empty JSON object)

Click Create.

Schedule frequency options

Choose frequency based on log volume and latency requirements:

Frequency	Cron Expression	Use Case
Every 5 minutes	`/5 * * *`	High-volume, low-latency
Every 15 minutes	`/15 * * *`	Medium volume
Every hour	`0 * * * *`	Standard (recommended)

Test the integration

In the Cloud Scheduler console, find your job.
Click Force run to trigger the job manually.
Wait a few seconds.
Go to Cloud Run > Services.
Click on your function name (proofpoint-wbi-collector).
Click the Logs tab.

Verify the function executed successfully. Look for:

Fetching events from last 3600 seconds
Retrieved X clicksPermitted events
Retrieved X messagesDelivered events
Total events retrieved: X
Wrote X records to gs://proofpoint-wbi-logs/wbi-logs/logs_YYYYMMDD_HHMMSS.ndjson
Successfully processed X records

Go to Cloud Storage > Buckets.
Click on your bucket name (proofpoint-wbi-logs).
Navigate to the prefix folder (wbi-logs/).
Verify that a new .ndjson file was created with the current timestamp.

If you see errors in the logs:

HTTP 401: Check the Service Principal and API Secret in environment variables
HTTP 403: Verify the credential has SIEM API access and browser isolation events are included in your subscription
HTTP 429: Rate limiting - function will automatically retry with backoff
Missing environment variables: Check all required variables are set

Retrieve the Google SecOps service account

Google SecOps uses a unique service account to read data from your GCS bucket. You must grant this service account access to your bucket.

Get the service account email

Go to SIEM Settings > Feeds.
Click Add New Feed.
Click Configure a single feed.
In the Feed name field, enter a name for the feed (for example, Proofpoint Web Browser Isolation Logs).
Select Google Cloud Storage V2 as the Source type.
Select Proofpoint Web Browser Isolation as the Log type.
Click Get Service Account.

A unique service account email will be displayed, for example:

chronicle-12345678@chronicle-gcp-prod.iam.gserviceaccount.com

Copy this email address for use in the next step.

Note: Each Google SecOps instance has a unique service account. Don't use service accounts from other documentation or examples.
Click Next.
Specify values for the following input parameters:
- Storage bucket URL: Enter the GCS bucket URI with the prefix path:
```
gs://proofpoint-wbi-logs/wbi-logs/
```
  - Replace:
    - proofpoint-wbi-logs: Your GCS bucket name.
    - wbi-logs: Optional prefix/folder path where logs are stored (leave empty for root).
Note: Always include the trailing slash (/) at the end of the URI.
- Source deletion option: Select the deletion option according to your preference:
  - Never: Never deletes any files after transfers (recommended for testing).
  - Delete transferred files: Deletes files after successful transfer.
  - Delete transferred files and empty directories: Deletes files and empty directories after successful transfer.
    
    Note: If you select a deletion option, the service account must have Storage Object Admin role instead of Storage Object Viewer. Update IAM permissions accordingly.
- Maximum File Age: Include files modified in the last number of days (default is 180 days)
- Asset namespace: The asset namespace
- Ingestion labels: The label to be applied to the events from this feed
Click Next.
Review your new feed configuration in the Finalize screen, and then click Submit.

Grant IAM permissions to the Google SecOps service account

The Google SecOps service account needs Storage Object Viewer role on your GCS bucket.

Go to Cloud Storage > Buckets.
Click on your bucket name (for example, proofpoint-wbi-logs).
Go to the Permissions tab.
Click Grant access.
Provide the following configuration details:
- Add principals: Paste the Google SecOps service account email
- Assign roles: Select Storage Object Viewer
Click Save.

Note: If you plan to use the deletion option "Delete transferred files" or "Delete transferred files and empty directories," grant Storage Object Admin role instead of Storage Object Viewer.

UDM mapping table

Log Field	UDM Mapping	Logic
	metadata.event_type	Type of the event
categories	metadata.product_event_type	Product-specific event type
parentPageURL	metadata.url_back_to_product	URL linking back to the product
region	principal.location.country_or_region	Country or region of the principal's location
zone	principal.location.name	Name of the principal's location
userId	principal.user.product_object_id	Product-specific identifier for the user
userName	principal.user.userid	User identifier
security_result	security_result	Security result details
disposition	security_result.action	Security action taken
disposition	security_result.action_details	Details of the security action
classification	security_result.detection_fields	Detection-related fields
url	target.url	URL of the target resource
	metadata.product_name	Product name
	metadata.vendor_name	Vendor name

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