Detection: Azure AD AzureHound UserAgent Detected

Updated Date: 2025-01-06 ID: d62852db-a1f1-40db-a7fc-c3d56fa8bda3 Author: Dean Luxton Type: TTP Product: Splunk Enterprise Security

Description

This detection identifies the presence of the default AzureHound user-agent string within Microsoft Graph Activity logs and NonInteractive SignIn Logs. AzureHound is a tool used for gathering information about Azure Active Directory environments, often employed by security professionals for legitimate auditing purposes. However, it can also be leveraged by malicious actors to perform reconnaissance activities, mapping out the Azure AD infrastructure to identify potential vulnerabilities and targets for further exploitation. Detecting its usage can help in identifying unauthorized access attempts and preemptively mitigating potential security threats to your Azure environment.

Search

1`azure_monitor_aad` category IN (MicrosoftGraphActivityLogs, NonInteractiveUserSignInLogs) properties.userAgent=azurehound* 
2| rename properties.userAgent as user_agent 
3| fillnull 
4| stats count min(_time) as firstTime max(_time) as lastTime by dest user src vendor_account vendor_product user_agent signature 
5| iplocation src 
6| `security_content_ctime(firstTime)` 
7| `security_content_ctime(lastTime)` 
8| `azure_ad_azurehound_useragent_detected_filter`

Data Source

Name	Platform	Sourcetype	Source
Azure Active Directory MicrosoftGraphActivityLogs	Azure	`'azure:monitor:aad'`	`'Azure AD'`
Azure Active Directory NonInteractiveUserSignInLogs	Azure	`'azure:monitor:aad'`	`'Azure AD'`

Macros Used

Name	Value
azure_monitor_aad	`sourcetype=azure:monitor:aad`
azure_ad_azurehound_useragent_detected_filter	`search *`

azure_ad_azurehound_useragent_detected_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
T1087.004	Cloud Account	Discovery
T1526	Cloud Service Discovery	Discovery

Exploitation

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

The Splunk Add-on for Microsoft Cloud Services add-on is required to ingest NonInteractiveUserSignInLogs and MicrosoftGraphActivityLogs via an Azure EventHub. See reference for links for further details.

Known False Positives

None

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

AzureHound UserAgent String $user_agent$ Detected on Tenant $dest$

Risk Object	Risk Object Type	Risk Score	Threat Objects
user	user	80	src

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`Azure AD`	`azure:monitor:aad`
Integration	✅ Passing	Dataset	`Azure AD`	`azure:monitor:aad`

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: 3