Detection: Windows AD Domain Controller Promotion

Updated Date: 2024-05-18 ID: e633a0ef-2a6e-4ed7-b925-5ff999e5d1f0 Author: Dean Luxton Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies a genuine Domain Controller (DC) promotion event by detecting when a computer assigns itself the necessary Service Principal Names (SPNs) to function as a domain controller. It leverages Windows Security Event Code 4742 to monitor existing domain controllers for these changes. This activity is significant as it can help identify rogue DCs added to the network, which could indicate a DCShadow attack. If confirmed malicious, this could allow an attacker to manipulate Active Directory, leading to potential privilege escalation and persistent access within the environment.

 1`wineventlog_security` EventCode=4742 ServicePrincipalNames IN ("*E3514235-4B06-11D1-AB04-00C04FC2DCD2/*","*GC/*")
 2| stats min(_time) as _time latest(ServicePrincipalNames) as ServicePrincipalNames,values(signature) as signature, values(src_user) as src_user, values(user) as user by Logon_ID, dvc
 3| where src_user=user
 4| rename Logon_ID as TargetLogonId, user as dest 
 5| appendpipe [
 6| map search="search `wineventlog_security` EventCode=4624 TargetLogonId=$TargetLogonId$" 
 7| fields - dest, dvc, signature]
 8| stats min(_time) as _time, values(TargetUserSid) as TargetUserSid, values(Target_Domain) as Target_Domain, values(user) as user, values(status) as status, values(src_category) as src_category, values(src_ip) as src_ip values(ServicePrincipalNames) as ServicePrincipalNames values(signature) as signature values(dest) as dest values(dvc) as dvc by TargetLogonId 
 9| eval dest=trim(dest,"$") 
10| `windows_ad_domain_controller_promotion_filter`

Data Source

Name Platform Sourcetype Source Supported App
Windows Event Log Security 4742 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Security' N/A

Macros Used

Name Value
wineventlog_security eventtype=wineventlog_security OR Channel=security OR source=XmlWinEventLog:Security
windows_ad_domain_controller_promotion_filter search *
windows_ad_domain_controller_promotion_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
T1207 Rogue Domain Controller Defense Evasion
KillChainPhase.EXPLOITAITON
NistCategory.DE_CM
Cis18Value.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

To successfully implement this search, you need to be ingesting eventcode 4742. The Advanced Security Audit policy setting Audit Computer Account Management within Account Management needs to be enabled.

Known False Positives

None.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
AD Domain Controller Promotion Event Detected for $dest$ 80 80 100
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 XmlWinEventLog:Security XmlWinEventLog
Integration ✅ Passing Dataset XmlWinEventLog:Security XmlWinEventLog

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: 2