Detection: WinEvent Windows Task Scheduler Event Action Started

Updated Date: 2024-10-24 ID: b3632472-310b-11ec-9aab-acde48001122 Author: Michael Haag, Splunk Type: Hunting Product: Splunk Enterprise Security

Description

The following analytic detects the execution of tasks registered in Windows Task Scheduler by monitoring EventID 200 (action run) and 201 (action completed) from the Task Scheduler logs. This detection leverages Task Scheduler logs to identify potentially suspicious or unauthorized task executions. Monitoring these events is significant for a SOC as it helps uncover evasive techniques used for persistence, unauthorized code execution, or other malicious activities. If confirmed malicious, this activity could lead to unauthorized access, data exfiltration, or the execution of harmful payloads, posing a significant threat to the environment.

Search

1`wineventlog_task_scheduler` EventCode IN ("200","201")  
2| stats count min(_time) as firstTime max(_time) as lastTime by TaskName dvc EventCode 
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)` 
5| `winevent_windows_task_scheduler_event_action_started_filter`

Data Source

Name	Platform	Sourcetype	Source
Windows Event Log TaskScheduler 200	Windows	`'wineventlog'`	`'WinEventLog:Microsoft-Windows-TaskScheduler/Operational'`

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
winevent_windows_task_scheduler_event_action_started_filter	`search *`

winevent_windows_task_scheduler_event_action_started_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
T1053.005	Scheduled Task	Execution

KillChainPhase.EXPLOITAITON

KillChainPhase.INSTALLATION

NistCategory.DE_AE

Cis18Value.CIS_10

APT-C-36

APT29

APT3

APT32

APT33

APT37

APT38

APT39

APT41

BITTER

BRONZE BUTLER

Blue Mockingbird

Chimera

Cobalt Group

Confucius

Daggerfly

Dragonfly

Ember Bear

FIN10

FIN13

FIN6

FIN7

FIN8

Fox Kitten

GALLIUM

Gamaredon Group

HEXANE

Higaisa

Kimsuky

Lazarus Group

LuminousMoth

Machete

Magic Hound

Molerats

Moonstone Sleet

MuddyWater

Mustang Panda

Naikon

OilRig

Patchwork

Rancor

RedCurl

Sandworm Team

Silence

Stealth Falcon

TA2541

ToddyCat

Winter Vivern

Wizard Spider

menuPass

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 Risk Event	False

This configuration file applies to all detections of type hunting.

Implementation

Task Scheduler logs are required to be collected. Enable logging with inputs.conf by adding a stanza for [WinEventLog://Microsoft-Windows-TaskScheduler/Operational] and renderXml=false. Note, not translating it in XML may require a proper extraction of specific items in the Message.

Known False Positives

False positives will be present. Filter based on ActionName paths or specify keywords of interest.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
A Scheduled Task was scheduled and ran on $dvc$.	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:Microsoft-Windows-TaskScheduler/Operational`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-TaskScheduler/Operational`	`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