Detection: Windows Increase in Group or Object Modification Activity

Updated Date: 2023-10-13 ID: 4f9564dd-a204-4f22-b375-4dfca3a68731 Author: Dean Luxton Type: TTP Product: Splunk Enterprise Security

Description

This analytic detects an increase in modifications to AD groups or objects. Frequent changes to AD groups or objects can indicate potential security risks, such as unauthorized access attempts, impairing defences or establishing persistence. By monitoring AD logs for unusual modification patterns, this detection helps identify suspicious behavior that could compromise the integrity and security of the AD environment.

Search

1`wineventlog_security` EventCode IN (4670,4727,4731,4734,4735,4764) 
2| bucket span=5m _time  
3| stats values(object) as object, dc(object) as objectCount, values(src_user_category) as src_user_category, values(dest) as dest, values(dest_category) as dest_category by _time, src_user, signature, status 
4| eventstats avg(objectCount) as comp_avg, stdev(objectCount) as comp_std by src_user, signature 
5| eval upperBound=(comp_avg+comp_std) 
6| eval isOutlier=if(objectCount > 10 and (objectCount >= upperBound), 1, 0) 
7| search isOutlier=1  
8| `windows_increase_in_group_or_object_modification_activity_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
Windows Event Log Security 4663	Windows	`'xmlwineventlog'`	`'XmlWinEventLog:Security'`	N/A

Macros Used

Name	Value
wineventlog_security	`eventtype=wineventlog_security OR Channel=security OR source=XmlWinEventLog:Security`
windows_increase_in_group_or_object_modification_activity_filter	`search *`

windows_increase_in_group_or_object_modification_activity_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
T1562	Impair Defenses	Privilege Escalation

KillChainPhase.EXPLOITAITON

KillChainPhase.INSTALLATION

NistCategory.DE_CM

Cis18Value.CIS_10

APT3

APT41

APT5

Dragonfly

FIN13

HAFNIUM

Kimsuky

Lazarus Group

Magic Hound

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

Run this detection looking over a 7 day timeframe for best results.

Known False Positives

Unknown

Associated Analytic Story

Sneaky Active Directory Persistence Tricks

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
Spike in Group or Object Modifications performed by $src_user$	8	20	40

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

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: 1