Collect Proofpoint TAP Forensics logs

Supported in:

Google secops SIEM

This document explains how to ingest Proofpoint TAP Forensics logs to Google Security Operations using Google Cloud Storage V2.

Proofpoint Targeted Attack Protection (TAP) is an advanced email security platform that detects, analyzes, and blocks threats delivered through email, including malicious attachments and URLs. The TAP Forensics API provides detailed forensic evidence about individual threats and campaigns observed in your environment, including sandbox analysis results, behavioral indicators, network activity, file system changes, and process execution data. These forensic indicators can be used to confirm compromise on a host, enrich security intelligence sources, or orchestrate updates to security endpoints.

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 create Cloud Run services, Pub/Sub topics, and Cloud Scheduler jobs
A Proofpoint TAP subscription with access to the Threat Insight Dashboard
TAP API service credentials (Service Principal and Secret) with permissions to access the SIEM API and Forensics API

Generate Proofpoint TAP API service credentials

Sign in to the Proofpoint TAP Threat Insight Dashboard.
Go to Settings > Connected Applications > Service Credentials.
Click Create New Credential.
In the Generated Service Credential dialog, copy and securely store:
- Service Principal: The principal identifier used for API authentication
- Secret: The secret key used for API authentication
Note: The Secret is displayed only once during creation. If lost, you must generate a new credential. Service credentials are required for all TAP API requests and use HTTP Basic Authentication.

Verify API access

Test your credentials before proceeding with the integration:

PRINCIPAL="your-service-principal"
SECRET="your-secret"

# Test SIEM API access (fetch last 5 minutes of events)
curl -s "https://tap-api-v2.proofpoint.com/v2/siem/all?format=json&sinceSeconds=300" \
  --user "${PRINCIPAL}:${SECRET}"

# Test Forensics API access (requires a valid threatId)
# curl -s "https://tap-api-v2.proofpoint.com/v2/forensics?threatId=<threatId>" \
#   --user "${PRINCIPAL}:${SECRET}"

A successful SIEM API response returns a JSON object containing messagesBlocked, messagesDelivered, clicksBlocked, and clicksPermitted arrays.

If you receive a 401 error, verify that your Service Principal and Secret are correct.
If you receive a 403 error, confirm that your account has TAP API access enabled.

Create a 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-tap-forensics-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.

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 the 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 tap-forensics-collector-sa
- Service account description: Enter Service account for Cloud Run function to collect Proofpoint TAP Forensics 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 forensic evidence data 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 your bucket name.
Go to the Permissions tab.
Click Grant access.
Provide the following configuration details:
- Add principals: Enter the service account email (for example, tap-forensics-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 tap-forensics-collector-trigger
- Leave other settings as default
Click Create.

Create a Cloud Run function to collect forensic evidence

The Cloud Run function will be triggered by Pub/Sub messages from Cloud Scheduler to fetch threat events from the Proofpoint TAP SIEM API, retrieve forensic evidence for each unique threat using the Forensics API, and write the results 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 tap-forensics-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 topic tap-forensics-collector-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 tap-forensics-collector-sa

Setting	Value
Service name	`tap-forensics-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-tap-forensics-logs`	GCS bucket name
`GCS_PREFIX`	`tap-forensics`	Prefix for log files
`STATE_KEY`	`tap-forensics/state.json`	State file path
`TAP_PRINCIPAL`	`your-service-principal`	TAP API Service Principal
`TAP_SECRET`	`your-secret`	TAP API Secret
`LOOKBACK_HOURS`	`1`	Initial lookback period in hours (max 7 days)
`MAX_THREATS`	`500`	Max unique threats to fetch forensics for per run

Scroll down in the Variables & Secrets section to Requests:
- Request timeout: Enter 540 seconds (9 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=10.0, 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', 'tap-forensics').strip('/')
STATE_KEY = os.environ.get('STATE_KEY') or f"{GCS_PREFIX}/state.json"
TAP_PRINCIPAL = os.environ.get('TAP_PRINCIPAL')
TAP_SECRET = os.environ.get('TAP_SECRET')
LOOKBACK_HOURS = int(os.environ.get('LOOKBACK_HOURS', '1'))
MAX_THREATS = int(os.environ.get('MAX_THREATS', '500'))

API_BASE = 'https://tap-api-v2.proofpoint.com'

def get_auth_header():
  """Build HTTP Basic Authentication header."""
  auth_string = f"{TAP_PRINCIPAL}:{TAP_SECRET}"
  auth_bytes = auth_string.encode('utf-8')
  auth_b64 = base64.b64encode(auth_bytes).decode('utf-8')
  return f"Basic {auth_b64}"

@functions_framework.cloud_event
def main(cloud_event):
  """
  Cloud Run function triggered by Pub/Sub to fetch Proofpoint TAP
  forensic evidence and write to GCS.

  The function first queries the SIEM API to discover threat IDs,
  then calls the Forensics API for each unique threat to retrieve
  detailed forensic evidence (sandbox results, behavioral
  indicators, network activity, file changes, and process data).

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

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

  try:
    bucket = storage_client.bucket(GCS_BUCKET)

    # Load state
    state = load_state(bucket, STATE_KEY)

    # Determine time window
    now = datetime.now(timezone.utc)
    last_time = None

    if isinstance(state, dict) and state.get('last_event_time'):
      try:
        last_time = parse_datetime(state['last_event_time'])
        # Overlap by 2 minutes to catch delayed events
        last_time = last_time - timedelta(minutes=2)
      except Exception as e:
        print(f"Warning: Could not parse last_event_time: {e}")

    if last_time is None:
      last_time = now - timedelta(hours=LOOKBACK_HOURS)

    # TAP SIEM API allows max 1 hour per request and max 7 days lookback
    if (now - last_time) > timedelta(days=7):
      last_time = now - timedelta(days=7)
      print("Warning: Lookback capped to 7 days (TAP API limit)")

    print(f"Fetching threats from {last_time.isoformat()} to {now.isoformat()}")

    # Step 1: Fetch threat IDs from the SIEM API
    threat_ids = fetch_threat_ids(last_time, now)

    if not threat_ids:
      print("No threats found in the specified time window.")
      save_state(bucket, STATE_KEY, now.isoformat())
      return

    print(f"Found {len(threat_ids)} unique threat IDs")

    # Step 2: Fetch forensic evidence for each threat
    forensic_records = fetch_forensics_for_threats(threat_ids)

    if not forensic_records:
      print("No forensic evidence retrieved.")
      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}/tap_forensics_{timestamp}.ndjson"
    blob = bucket.blob(object_key)

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

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

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

    print(f"Successfully processed forensics for {len(threat_ids)} threats")

  except Exception as e:
    print(f'Error processing TAP forensics: {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):
  """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 parse_datetime(value):
  """Parse ISO datetime string to datetime object."""
  if value.endswith('Z'):
    value = value[:-1] + '+00:00'
  return datetime.fromisoformat(value)

def fetch_threat_ids(start_time, end_time):
  """
  Fetch unique threat IDs from the TAP SIEM API by querying
  in 1-hour intervals within the specified time window.

  Args:
    start_time: Start of the time window (datetime)
    end_time: End of the time window (datetime)

  Returns:
    Set of unique threat ID strings
  """
  headers = {
    'Authorization': get_auth_header(),
    'Accept': 'application/json',
    'User-Agent': 'GoogleSecOps-TAPForensicsCollector/1.0',
  }

  threat_ids = set()
  current_start = start_time
  backoff = 1.0

  while current_start < end_time:
    # TAP SIEM API allows max 1 hour per request
    current_end = min(current_start + timedelta(hours=1), end_time)

    interval = (
      f"{current_start.strftime('%Y-%m-%dT%H:%M:%SZ')}"
      f"/{current_end.strftime('%Y-%m-%dT%H:%M:%SZ')}"
    )
    url = f"{API_BASE}/v2/siem/all?format=json&interval={interval}"

    try:
      response = http.request('GET', url, headers=headers)

      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, 60.0)
        continue

      backoff = 1.0

      if response.status != 200:
        print(f"SIEM API HTTP Error: {response.status}")
        response_text = response.data.decode('utf-8')
        print(f"Response body: {response_text[:500]}")
        current_start = current_end
        continue

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

      # Extract threat IDs from all event types
      for key in ['messagesBlocked', 'messagesDelivered']:
        for msg in data.get(key, []):
          for threat_info in msg.get('threatsInfoMap', []):
            tid = threat_info.get('threatID')
            if tid:
              threat_ids.add(tid)

      for key in ['clicksBlocked', 'clicksPermitted']:
        for click in data.get(key, []):
          tid = click.get('threatID')
          if tid:
            threat_ids.add(tid)

      event_count = sum(
        len(data.get(k, []))
        for k in [
          'messagesBlocked',
          'messagesDelivered',
          'clicksBlocked',
          'clicksPermitted',
        ]
      )
      print(
        f"Interval {interval}: {event_count} events, "
        f"{len(threat_ids)} unique threats so far"
      )

    except Exception as e:
      print(f"Error fetching SIEM events: {e}")

    current_start = current_end

    if len(threat_ids) >= MAX_THREATS:
      print(f"Reached max threats limit ({MAX_THREATS})")
      break

  return threat_ids

def fetch_forensics_for_threats(threat_ids):
  """
  Fetch forensic evidence for each threat ID from the
  Forensics API.

  Args:
    threat_ids: Set of threat ID strings

  Returns:
    List of forensic report dictionaries
  """
  headers = {
    'Authorization': get_auth_header(),
    'Accept': 'application/json',
    'User-Agent': 'GoogleSecOps-TAPForensicsCollector/1.0',
  }

  records = []
  backoff = 1.0
  processed = 0
  skipped = 0

  for threat_id in list(threat_ids)[:MAX_THREATS]:
    url = (
      f"{API_BASE}/v2/forensics"
      f"?threatId={threat_id}"
      f"&includeCampaignForensics=true"
    )

    try:
      response = http.request('GET', url, headers=headers)

      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, 60.0)
        # Retry the same threat
        continue

      backoff = 1.0

      if response.status == 204:
        skipped += 1
        processed += 1
        continue

      if response.status != 200:
        print(
          f"Forensics API error for {threat_id}: "
          f"HTTP {response.status}"
        )
        skipped += 1
        processed += 1
        continue

      data = json.loads(response.data.decode('utf-8'))
      reports = data.get('reports', [])

      if reports:
        # Add the threat ID to each report for correlation
        for report in reports:
          report['_threatId'] = threat_id
        records.extend(reports)

      processed += 1

      if processed % 50 == 0:
        print(
          f"Progress: {processed}/{len(threat_ids)} threats, "
          f"{len(records)} forensic reports collected"
        )

    except Exception as e:
      print(f"Error fetching forensics for {threat_id}: {e}")
      skipped += 1
      processed += 1

  print(
    f"Forensics collection complete: {processed} threats processed, "
    f"{skipped} skipped, {len(records)} reports collected"
  )
  return records

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 function first queries the TAP SIEM API /v2/siem/all endpoint to discover threat IDs from recent email security events, then calls the Forensics API /v2/forensics for each unique threat to retrieve detailed forensic evidence including sandbox results, behavioral indicators, DNS queries, network connections, file modifications, and process activity. The SIEM API supports a maximum of 1 hour per request and 7 days of lookback. The function automatically splits larger time windows into 1-hour intervals.

Create a 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	`tap-forensics-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 topic `tap-forensics-collector-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 15 minutes	`/15 * * *`	High-volume environments with many threats
Every hour	`0 * * * *`	Standard (recommended)
Every 6 hours	`0 /6 * *`	Low-volume environments

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 the function name tap-forensics-collector.
Click the Logs tab.

Verify the function executed successfully. Look for:

Fetching threats from YYYY-MM-DDTHH:MM:SS+00:00 to YYYY-MM-DDTHH:MM:SS+00:00
Interval .../...: X events, Y unique threats so far
Found Z unique threat IDs
Forensics collection complete: Z threats processed, 0 skipped, N reports collected
Wrote N records to gs://proofpoint-tap-forensics-logs/tap-forensics/tap_forensics_YYYYMMDD_HHMMSS.ndjson
Successfully processed forensics for Z threats

Go to Cloud Storage > Buckets.
Click your bucket name.
Navigate to the prefix folder tap-forensics/.
Verify that a new .ndjson file was created with the current timestamp.

If you see errors in the logs:

HTTP 401: Check TAP_PRINCIPAL and TAP_SECRET in environment variables. Verify the Service Principal and Secret are correct.
HTTP 403: Confirm that your TAP account has API access enabled.
HTTP 429: Rate limiting - function will automatically retry with backoff. Consider reducing schedule frequency.
No threats found: This is normal if no threats were detected in the time window. TAP only reports threats identified by URL Defense or Attachment Defense.
Missing environment variables: Check all required variables are set.

Configure a feed in Google SecOps to ingest Proofpoint TAP Forensics logs

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 TAP Forensics).
Select Google Cloud Storage V2 as the Source type.
Select Proofpoint Tap Forensics 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-tap-forensics-logs/tap-forensics/
```
  - Replace:
    - proofpoint-tap-forensics-logs: Your GCS bucket name.
    - tap-forensics: 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 your bucket name.
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
`malicious_label`	`additional.fields`	Merged
`threat_type_label`	`additional.fields`	Merged
`generated`	`metadata.event_timestamp`	Parsed as `ISO8601`
`has_principal`	`metadata.event_type`	Mapped: `true` → `STATUS_UPDATE`
`protocol`	`network.ip_protocol`	Directly mapped
`prin_ip`	`principal.asset.ip`	Merged
`domain`	`principal.domain.name`	Directly mapped
`path`	`principal.file.full_path`	Directly mapped
`file_hash_sha256`	`principal.file.sha256`	Directly mapped
`prin_ip`	`principal.ip`	Merged
`port`	`principal.port`	Directly mapped
`url`	`principal.url`	Directly mapped
`_security_result`	`security_result`	Merged
N/A	`metadata.event_type`	Constant: `STATUS_UPDATE`
N/A	`metadata.product_event_type`	Constant: `Forensic Reports`
N/A	`metadata.product_name`	Constant: `TAP Forensics`
N/A	`metadata.vendor_name`	Constant: `Proofpoint`
N/A	`principal.asset.platform_software.platform`	Constant: `WINDOWS`

Need more help? Get answers from Community members and Google SecOps professionals.