Detection: Azure Runbook Webhook Created

Updated Date: 2025-05-02 ID: e98944a9-92e4-443c-81b8-a322e33ce75a Author: Mauricio Velazco, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the creation of a new Automation Runbook Webhook within an Azure tenant. It leverages Azure Audit events, specifically the "Create or Update an Azure Automation webhook" operation, to identify this activity. This behavior is significant because Webhooks can trigger Automation Runbooks via unauthenticated URLs exposed to the Internet, posing a security risk. If confirmed malicious, an attacker could use this to execute code, create users, or maintain persistence within the environment, potentially leading to unauthorized access and control over Azure resources.

1`azure_audit` operationName.localizedValue="Create or Update an Azure Automation webhook" status.value=Succeeded 
2| dedup object 
3| rename claims.ipaddr as src_ip 
4| rename caller as user 
5| stats count min(_time) as firstTime max(_time) as lastTime values(dest) as dest by object user, src_ip, resourceGroupName, object_path 
6| `security_content_ctime(firstTime)` 
7| `security_content_ctime(lastTime)` 
8| `azure_runbook_webhook_created_filter`

Data Source

Name Platform Sourcetype Source
Azure Audit Create or Update an Azure Automation webhook Azure icon Azure 'mscs:azure:audit' 'mscs:azure:audit'

Macros Used

Name Value
azure_audit sourcetype=mscs:azure:audit
azure_runbook_webhook_created_filter search *
azure_runbook_webhook_created_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1078.004 Cloud Accounts Defense Evasion
Delivery
Exploitation
Installation
DE.CM
CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Notable Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Risk Event True
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

You must install the latest version of Splunk Add-on for Microsoft Cloud Services from Splunkbase (https://splunkbase.splunk.com/app/3110/#/details). You must be ingesting Azure Audit events into your Splunk environment. Specifically, this analytic leverages the Azure Activity log category.

Known False Positives

Administrators may legitimately create Azure Runbook Webhooks. Filter as needed.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

A new Azure Runbook Webhook $object$ was created by $user$

Risk Object Risk Object Type Risk Score Threat Objects
user user 63 No Threat Objects

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset mscs:azure:audit mscs:azure:audit
Integration ✅ Passing Dataset mscs:azure:audit mscs:azure:audit

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 10