ID | Technique | Tactic |
---|---|---|
T1078 | Valid Accounts | Defense Evasion |
T1078.004 | Cloud Accounts | Initial Access |
Detection: Azure Runbook Webhook Created
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.
Search
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 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 | Supported App |
---|---|---|---|---|
Azure Audit Create or Update an Azure Automation webhook | Azure | 'mscs:azure:audit' |
'mscs:azure:audit' |
N/A |
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
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 |
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 | Risk Score | Impact | Confidence |
---|---|---|---|
A new Azure Runbook Webhook $object$ was created by $user$ | 63 | 70 | 90 |
References
-
https://docs.microsoft.com/en-us/azure/automation/automation-runbook-types
-
https://docs.microsoft.com/en-us/azure/automation/automation-webhooks?tabs=portal
-
https://www.inversecos.com/2021/12/how-to-detect-malicious-azure.html
-
https://microsoft.github.io/Azure-Threat-Research-Matrix/Persistence/AZT503/AZT503-3/
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: 5