Detection: Windows AD Privileged Group Modification

EXPERIMENTAL DETECTION

This detection status is set to experimental. The Splunk Threat Research team has not yet fully tested, simulated, or built comprehensive datasets for this detection. As such, this analytic is not officially supported. If you have any questions or concerns, please reach out to us at research@splunk.com.

Updated Date: 2024-10-17 ID: 187bf937-c436-4c65-bbcb-7539ffe02da1 Author: Dean Luxton Type: TTP Product: Splunk Enterprise Security

Description

Detect users added to privileged AD Groups.

1`wineventlog_security` EventCode IN (4728) 
2| stats min(_time) as _time dc(user) as usercount, values(user) as user values(user_category) as user_category values(src_user_category) as src_user_category values(dvc) as dvc by signature, Group_Name,src_user 
3| lookup admon_groups_def  cn as Group_Name OUTPUT category 
4| where category="privileged" 
5| `windows_ad_privileged_group_modification_filter`

Data Source

No data sources specified for this detection.

Macros Used

Name Value
wineventlog_security eventtype=wineventlog_security OR Channel=security OR source=XmlWinEventLog:Security
windows_ad_privileged_group_modification_filter search *
windows_ad_privileged_group_modification_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
T1098 Account Manipulation Persistence
KillChainPhase.EXPLOITAITON
KillChainPhase.INSTALLATION
NistCategory.DE_CM
Cis18Value.CIS_10
HAFNIUM
Lazarus Group

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

This analytic requires eventCode 4728 to be ingested along with the admon_groups_def lookup being configured to include a list of AD groups along with a category to identify privileged groups. See splunkbase app listed in the references for further details.

Known False Positives

None

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
$user$ was added to privileged AD Group $Group_Name$ by $src_user$ 50 50 100
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 Not Applicable N/A N/A N/A
Unit ❌ Failing Dataset XmlWinEventLog:Security XmlWinEventLog
Integration ❌ Failing 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: 3