Detection: Powershell COM Hijacking InprocServer32 Modification

Updated Date: 2024-09-30 ID: ea61e291-af05-4716-932a-67faddb6ae6f Author: Michael Haag, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects attempts to modify or add a Component Object Model (COM) entry to the InProcServer32 path within the registry using PowerShell. It leverages PowerShell ScriptBlock Logging (EventCode 4104) to identify suspicious script blocks that target the InProcServer32 registry path. This activity is significant because modifying COM objects can be used for persistence or privilege escalation by attackers. If confirmed malicious, this could allow an attacker to execute arbitrary code or maintain persistent access to the compromised system, posing a severe security risk.

Search

1`powershell` EventCode=4104 ScriptBlockText = "*Software\\Classes\\CLSID\\*\\InProcServer32*" 
2| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer UserID 
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)` 
5| `powershell_com_hijacking_inprocserver32_modification_filter`

Data Source

Name	Platform	Sourcetype	Source
Powershell Script Block Logging 4104	Windows	`'xmlwineventlog'`	`'XmlWinEventLog:Microsoft-Windows-PowerShell/Operational'`

Macros Used

Name	Value
powershell	`(source=WinEventLog:Microsoft-Windows-PowerShell/Operational OR source="XmlWinEventLog:Microsoft-Windows-PowerShell/Operational")`
powershell_com_hijacking_inprocserver32_modification_filter	`search *`

powershell_com_hijacking_inprocserver32_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
T1546.015	Component Object Model Hijacking	Persistence
T1059	Command and Scripting Interpreter	Privilege Escalation
T1059.001	PowerShell	Execution

KillChainPhase.EXPLOITAITON

KillChainPhase.INSTALLATION

NistCategory.DE_CM

Cis18Value.CIS_10

APT28

APT19

APT32

APT37

APT39

Dragonfly

FIN5

FIN6

FIN7

Fox Kitten

Ke3chang

OilRig

Saint Bear

Stealth Falcon

Whitefly

Windigo

Winter Vivern

APT19

APT28

APT29

APT3

APT32

APT33

APT38

APT39

APT41

APT5

Aquatic Panda

BRONZE BUTLER

Blue Mockingbird

CURIUM

Chimera

Cinnamon Tempest

Cobalt Group

Confucius

CopyKittens

Daggerfly

DarkHydrus

DarkVishnya

Deep Panda

Dragonfly

Earth Lusca

Ember Bear

FIN10

FIN13

FIN6

FIN7

FIN8

Fox Kitten

GALLIUM

GOLD SOUTHFIELD

Gallmaker

Gamaredon Group

Gorgon Group

HAFNIUM

HEXANE

Inception

Indrik Spider

Kimsuky

Lazarus Group

LazyScripter

Leviathan

Magic Hound

Molerats

MoustachedBouncer

MuddyWater

Mustang Panda

Nomadic Octopus

OilRig

Patchwork

Play

Poseidon Group

RedCurl

Saint Bear

Sandworm Team

Sidewinder

Silence

Stealth Falcon

TA2541

TA459

TA505

TeamTNT

Threat Group-3390

Thrip

ToddyCat

Tonto Team

Turla

Volt Typhoon

WIRTE

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 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

The following analytic requires PowerShell operational logs to be imported. Modify the PowerShell macro as needed to match the sourcetype or add index. This analytic is specific to 4104, or PowerShell Script Block Logging.

Known False Positives

False positives will be present if any scripts are adding to inprocserver32. Filter as needed.

Associated Analytic Story

Malicious PowerShell

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
A PowerShell script has been identified with InProcServer32 within the script code 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:Microsoft-Windows-PowerShell/Operational`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-PowerShell/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: 3