Detection: Azure AD Successful PowerShell Authentication

Updated Date: 2024-09-30 ID: 62f10052-d7b3-4e48-b57b-56f8e3ac7ceb Author: Mauricio Velazco, Gowthamaraj Rajendran, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies a successful authentication event against an Azure AD tenant using PowerShell cmdlets. This detection leverages Azure AD SignInLogs to identify successful logins where the appDisplayName is "Microsoft Azure PowerShell." This activity is significant because it is uncommon for regular, non-administrative users to authenticate using PowerShell, and it may indicate enumeration and discovery techniques by an attacker. If confirmed malicious, this activity could allow attackers to perform extensive reconnaissance, potentially leading to privilege escalation or further exploitation within the Azure environment.

1`azure_monitor_aad`  category=SignInLogs properties.authenticationDetails{}.succeeded=true properties.appDisplayName="Microsoft Azure PowerShell" 
2| rename properties.*  as * 
3| stats count min(_time) as firstTime max(_time) as lastTime values(user) as user by src_ip, appDisplayName, user_agent 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `azure_ad_successful_powershell_authentication_filter`

Data Source

Name Platform Sourcetype Source
Azure Active Directory Azure icon Azure 'azure:monitor:aad' 'Azure AD'

Macros Used

Name Value
azure_monitor_aad sourcetype=azure:monitor:aad
azure_ad_successful_powershell_authentication_filter search *
azure_ad_successful_powershell_authentication_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
T1586 Compromise Accounts Resource Development
T1586.003 Cloud Accounts Resource Development
T1078 Valid Accounts Defense Evasion
T1078.004 Cloud Accounts Initial Access
KillChainPhase.DELIVERY
KillChainPhase.EXPLOITAITON
KillChainPhase.INSTALLATION
KillChainPhase.WEAPONIZATION
NistCategory.DE_CM
Cis18Value.CIS_10
APT29
APT18
APT28
APT29
APT33
APT39
APT41
Akira
Axiom
Carbanak
Chimera
Cinnamon Tempest
Dragonfly
FIN10
FIN4
FIN5
FIN6
FIN7
FIN8
Fox Kitten
GALLIUM
INC Ransom
Indrik Spider
Ke3chang
LAPSUS$
Lazarus Group
Leviathan
OilRig
POLONIUM
PittyTiger
Play
Sandworm Team
Silence
Silent Librarian
Star Blizzard
Suckfly
Threat Group-3390
Volt Typhoon
Wizard Spider
menuPass
APT28
APT29
APT33
APT5
Ke3chang
LAPSUS$

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 Active Directory events into your Splunk environment through an EventHub. This analytic was written to be used with the azure:monitor:aad sourcetype leveraging the Signin log category.

Known False Positives

Administrative users will likely use PowerShell commandlets to troubleshoot and maintain the environment. Filter as needed.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Successful authentication for user $user$ using PowerShell. 54 60 90
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

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: 5