Detection: Windows AD Short Lived Server Object

Description

The following analytic identifies the creation and quick deletion of a Domain Controller (DC) object within 30 seconds in an Active Directory environment, indicative of a potential DCShadow attack. This detection leverages Windows Security Event Codes 5137 and 5141, analyzing the duration between these events. This activity is significant as DCShadow allows attackers with privileged access to register a rogue DC, enabling unauthorized changes to AD objects, including credentials. If confirmed malicious, this could lead to unauthorized AD modifications, compromising the integrity and security of the entire domain.

1`wineventlog_security` EventCode=5137 OR EventCode=5141 ObjectDN="*CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration*" 
2| transaction ObjectDN startswith=(EventCode=5137) endswith=(EventCode=5141) 
3| eval short_lived=case((duration<30),"TRUE") 
4| search short_lived = TRUE 
5| stats values(ObjectDN) values(signature) values(EventCode) by _time, Computer, SubjectUserName 
6| `windows_ad_short_lived_server_object_filter`

Data Source

Name Platform Sourcetype Source
Windows Event Log Security 5137 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Security'
Windows Event Log Security 5141 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Security'

Macros Used

Name Value
wineventlog_security eventtype=wineventlog_security OR Channel=security OR source=XmlWinEventLog:Security
windows_ad_short_lived_server_object_filter search *
windows_ad_short_lived_server_object_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 ned to be ingesting Event codes 5137 and 5141. The Advanced Security Audit policy setting Audit Directory Services Changes within DS Access needs to be enabled. For these event codes to be generated, specific SACLs are required.

Known False Positives

Creating and deleting a server object within 30 seconds or less is unusual but not impossible in a production environment. Filter as needed.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Potential DCShadow Attack Detected on $Computer$ 64 80 80
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: 5