Collect Duo Telephony logs

Supported in:

Google secops SIEM

This document explains how to ingest Duo Telephony logs to Google Security Operations using Google Cloud Storage. The parser extracts fields from the logs, transforms and maps them to the Unified Data Model (UDM). It handles various Duo log formats, converting timestamps, extracting user information, network details, and security results, and finally structuring the output into the standardized UDM format.

Before you begin

Ensure that 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 Duo Admin Panel with Owner role

Collect Duo prerequisites (API credentials)

Sign in to the Duo Admin Panel as an administrator with the Owner role.
Go to Applications > Application Catalog.
Locate the entry for Admin API in the catalog.
Click + Add to create the application.
Copy and save in a secure location the following details:
- Integration Key
- Secret Key
- API Hostname (for example, api-yyyyyyyy.duosecurity.com)
In the Permissions section, check only the Read Telephony permission checkbox and deselect all other permissions.
Click Save Changes.

Verify permissions

To verify the Admin API application has the required permissions:

Sign in to the Duo Admin Panel.
Go to Applications > Protect an Application.
Locate your Admin API application.
Click the application name to view details.
In the Permissions section, verify that only Read Telephony is checked.
If other permissions are checked or Read Telephony is not checked, update the permissions and click Save Changes.

Test API access

Test your credentials before proceeding with the integration:

# Replace with your actual credentials
DUO_IKEY="your-integration-key"
DUO_SKEY="your-secret-key"
DUO_HOST="api-yyyyyyyy.duosecurity.com"

# Test API access (requires signing - use Duo's API test tool or Python script)
# Visit https://duo.com/docs/adminapi#testing to test your credentials

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, `duo-telephony-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 service account for 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 duo-telephony-collector-sa.
- Service account description: Enter Service account for Cloud Run function to collect Duo Telephony 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 your bucket name (for example, duo-telephony-logs).
Go to the Permissions tab.
Click Grant access.
Provide the following configuration details:
- Add principals: Enter the service account email (for example, duo-telephony-collector-sa@PROJECT_ID.iam.gserviceaccount.com).
- Assign roles: Select Storage Object Admin.
Click Save.

Create 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 duo-telephony-trigger.
- Leave other settings as default.
Click Create.

Create Cloud Run function to collect logs

The Cloud Run function is triggered by Pub/Sub messages from Cloud Scheduler to fetch logs from Duo Telephony API and writes 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 duo-telephony-logs-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 (duo-telephony-trigger).
4. Click Save.
In the Authentication section:
1. Select Require authentication.
2. Check Identity and Access Management (IAM).
Note: Pub/Sub automatically handles authentication when invoking the function.
Scroll down and expand Containers, Networking, Security.
Go to the Security tab:
- Service account: Select the service account (duo-telephony-collector-sa).

Setting	Value
Service name	`duo-telephony-logs-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
`GCS_BUCKET`	`duo-telephony-logs`
`GCS_PREFIX`	`duo-telephony`
`STATE_KEY`	`duo-telephony/state.json`
`DUO_IKEY`	`<your-integration-key>`
`DUO_SKEY`	`<your-secret-key>`
`DUO_API_HOST`	`api-yyyyyyyy.duosecurity.com`
`MAX_ITERATIONS`	`10`

Scroll down in the Variables & Secrets tab to Requests:
- Request timeout: Enter 600 seconds (10 minutes).
Go to the Settings tab in Containers:
- In the Resources section:
  - Memory: Select 512 MiB or higher.
  - CPU: Select 1.
- Click Done.
Scroll to Execution environment:
- Select Default (recommended).
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 opens 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 hmac
import hashlib
import base64
import urllib.parse
import urllib3
import email.utils
from datetime import datetime, timedelta, timezone
from typing import Dict, Any, List, Optional

# Initialize HTTP client with timeouts
http = urllib3.PoolManager(
    timeout=urllib3.Timeout(connect=5.0, read=30.0),
    retries=False,
)

# Initialize Storage client
storage_client = storage.Client()

@functions_framework.cloud_event
def main(cloud_event):
    """
    Cloud Run function triggered by Pub/Sub to fetch Duo telephony logs and write to GCS.

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

    # Get environment variables
    bucket_name = os.environ.get('GCS_BUCKET')
    prefix = os.environ.get('GCS_PREFIX', 'duo-telephony').rstrip('/')
    state_key = os.environ.get('STATE_KEY', 'duo-telephony/state.json')
    integration_key = os.environ.get('DUO_IKEY')
    secret_key = os.environ.get('DUO_SKEY')
    api_hostname = os.environ.get('DUO_API_HOST')

    if not all([bucket_name, integration_key, secret_key, api_hostname]):
        print('Error: Missing required environment variables')
        return

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

        # Load state
        state = load_state(bucket, state_key)

        # Calculate time range
        now = datetime.now(timezone.utc)

        if state.get('last_offset'):
            # Continue from last offset
            next_offset = state['last_offset']
            logs = []
            has_more = True
        else:
            # Start from last timestamp or 24 hours ago
            mintime = state.get('last_timestamp_ms', int((now - timedelta(hours=24)).timestamp() * 1000))
            # Apply 2-minute delay as recommended by Duo
            maxtime = int((now - timedelta(minutes=2)).timestamp() * 1000)
            next_offset = None
            logs = []
            has_more = True

        # Fetch logs with pagination
        total_fetched = 0
        max_iterations = int(os.environ.get('MAX_ITERATIONS', '10'))

        while has_more and total_fetched < max_iterations:
            page_num = total_fetched + 1

            if next_offset:
                # Use offset for pagination
                params = {
                    'limit': '100',
                    'next_offset': next_offset
                }
            else:
                # Initial request with time range
                params = {
                    'mintime': str(mintime),
                    'maxtime': str(maxtime),
                    'limit': '100',
                    'sort': 'ts:asc'
                }

            # Make API request with retry logic
            response = duo_api_call_with_retry(
                'GET',
                api_hostname,
                '/admin/v2/logs/telephony',
                params,
                integration_key,
                secret_key
            )

            if 'items' in response:
                logs.extend(response['items'])
                total_fetched += 1

            # Check for more data
            if 'metadata' in response and 'next_offset' in response['metadata']:
                next_offset = response['metadata']['next_offset']
                state['last_offset'] = next_offset
            else:
                has_more = False
                state['last_offset'] = None

                # Update timestamp for next run
                if logs:
                    # Get the latest timestamp from logs (ISO 8601 format)
                    latest_ts = max([log.get('ts', '') for log in logs])
                    if latest_ts:
                        # Convert ISO timestamp to milliseconds
                        dt = datetime.fromisoformat(latest_ts.replace('Z', '+00:00'))
                        state['last_timestamp_ms'] = int(dt.timestamp() * 1000) + 1

        # Save logs to GCS if any were fetched
        if logs:
            timestamp = datetime.now(timezone.utc).strftime('%Y%m%d_%H%M%S')
            blob_name = f"{prefix}/telephony_{timestamp}.json"

            # Format logs as newline-delimited JSON
            log_data = '\n'.join(json.dumps(log) for log in logs)

            blob = bucket.blob(blob_name)
            blob.upload_from_string(
                log_data,
                content_type='application/x-ndjson'
            )

            print(f"Saved {len(logs)} telephony logs to gs://{bucket_name}/{blob_name}")
        else:
            print("No new telephony logs found")

        # Save state
        save_state(bucket, state_key, state)

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

def duo_api_call_with_retry(
    method: str,
    host: str,
    path: str,
    params: Dict[str, str],
    ikey: str,
    skey: str,
    max_retries: int = 3
) -> Dict[str, Any]:
    """Make an authenticated API call to Duo Admin API with retry logic."""
    for attempt in range(max_retries):
        try:
            return duo_api_call(method, host, path, params, ikey, skey)
        except Exception as e:
            if '429' in str(e) or '5' in str(e)[:1]:
                if attempt < max_retries - 1:
                    wait_time = (2 ** attempt) * 2
                    print(f"Retrying after {wait_time} seconds...")
                    import time
                    time.sleep(wait_time)
                    continue
            raise

def duo_api_call(
    method: str,
    host: str,
    path: str,
    params: Dict[str, str],
    ikey: str,
    skey: str
) -> Dict[str, Any]:
    """Make an authenticated API call to Duo Admin API."""
    # Create canonical string for signing using RFC 2822 date format
    now = email.utils.formatdate()
    canon = [now, method.upper(), host.lower(), path]

    # Add parameters
    args = []
    for key in sorted(params.keys()):
        val = params[key]
        args.append(f"{urllib.parse.quote(key, '~')}={urllib.parse.quote(val, '~')}")
    canon.append('&'.join(args))

    canon_str = '\n'.join(canon)

    # Sign the request
    sig = hmac.new(
        skey.encode('utf-8'),
        canon_str.encode('utf-8'),
        hashlib.sha1
    ).hexdigest()

    # Create authorization header
    auth = base64.b64encode(f"{ikey}:{sig}".encode('utf-8')).decode('utf-8')

    # Build URL
    url = f"https://{host}{path}"
    if params:
        url += '?' + '&'.join(args)

    # Make request
    headers = {
        'Authorization': f'Basic {auth}',
        'Date': now,
        'Host': host,
        'User-Agent': 'duo-telephony-gcs-ingestor/1.0'
    }

    try:
        response = http.request('GET', url, headers=headers)
        data = json.loads(response.data.decode('utf-8'))

        if data.get('stat') == 'OK':
            return data.get('response', {})
        else:
            raise Exception(f"API error: {data.get('message', 'Unknown error')}")
    except urllib3.exceptions.HTTPError as e:
        raise Exception(f"HTTP error: {str(e)}")

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: {str(e)}')
    return {}

def save_state(bucket, key, state):
    """Save state to GCS."""
    try:
        blob = bucket.blob(key)
        blob.upload_from_string(
            json.dumps(state),
            content_type='application/json'
        )
    except Exception as e:
        print(f'Warning: Could not save state: {str(e)}')

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. Duo API rate limits are 5 requests per second and 1000 requests per minute. The function uses a limit of 100 records per page (instead of the maximum 1000) for better API performance and compliance with Duo's recommendations.

Create Cloud Scheduler job

Cloud Scheduler publishes 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	`duo-telephony-logs-1h`
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 (`duo-telephony-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)
Every 6 hours	`0 /6 * *`	Low volume, batch processing
Daily	`0 0 * * *`	Historical data collection

Test the scheduler job

In the Cloud Scheduler console, find your job (duo-telephony-logs-1h).
Click Force run to trigger manually.
Wait a few seconds and go to Cloud Run > Services.
Click on the function name (duo-telephony-logs-collector).
Click the Logs tab.
Verify the function executed successfully.
Go to Cloud Storage > Buckets.
Click your bucket name (duo-telephony-logs).
Navigate to the prefix folder (duo-telephony/).
Verify that a new .json file was created with logs.

If you see errors in the logs:

HTTP 401: Check API credentials (DUO_IKEY, DUO_SKEY, DUO_API_HOST) in environment variables
HTTP 403: Verify the Admin API application has Read Telephony permission enabled
HTTP 429: Rate limiting - function will automatically retry with exponential backoff
Missing environment variables: Check all required variables are set in the Cloud Run function configuration

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, Duo Telephony logs).
Select Google Cloud Storage V2 as the Source type.
Select Duo Telephony Logs as the Log type.
Click Get Service Account. A unique service account email is 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.

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 (for example, duo-telephony-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.

Configure a feed in Google SecOps to ingest Duo Telephony 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, Duo Telephony logs).
Select Google Cloud Storage V2 as the Source type.
Select Duo Telephony Logs as the Log type.
Click Next.
Specify values for the following input parameters:
- Storage bucket URL: Enter the GCS bucket URI with the prefix path:
```
gs://duo-telephony-logs/duo-telephony/
```
  - Replace:
    - duo-telephony-logs: Your GCS bucket name.
    - duo-telephony: Optional prefix/folder path where logs are stored (leave empty for root).
  - Examples:
    - Root bucket: gs://duo-telephony-logs/
    - With prefix: gs://duo-telephony-logs/duo-telephony/
  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.

UDM mapping table

Log field	UDM mapping	Logic
context	metadata.product_event_type	Directly mapped from the context field in the raw log.
credits	security_result.detection_fields.value	Directly mapped from the credits field in the raw log, nested under a detection_fields object with the corresponding key credits.
eventtype	security_result.detection_fields.value	Directly mapped from the eventtype field in the raw log, nested under a detection_fields object with the corresponding key eventtype.
host	principal.hostname	Directly mapped from the host field in the raw log if it's not an IP address.
	security_result.action	Set to a static value of "ALLOW" in the parser.
	security_result.detection_fields.value	Set to a static value of "MECHANISM_UNSPECIFIED" in the parser.
	metadata.event_timestamp	Parsed from the ts field in the raw log, which is an ISO 8601 timestamp string.
	metadata.event_type	Set to "USER_UNCATEGORIZED" if both context and host fields are present in the raw log. Set to "STATUS_UPDATE" if only host is present. Otherwise, set to "GENERIC_EVENT".
	metadata.log_type	Directly taken from the raw log's log_type field.
	metadata.product_name	Set to a static value of "Telephony" in the parser.
	metadata.vendor_name	Set to a static value of "Duo" in the parser.
phone	principal.user.phone_numbers	Directly mapped from the phone field in the raw log.
phone	principal.user.userid	Directly mapped from the phone field in the raw log.
	security_result.severity	Set to a static value of "INFORMATIONAL" in the parser.
	security_result.summary	Set to a static value of "Duo Telephony" in the parser.
ts	metadata.event_timestamp	Parsed from the ts field in the raw log, which is an ISO 8601 timestamp string.
type	security_result.summary	Directly mapped from the type field in the raw log.

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