Detection: Windows Privilege Escalation System Process Without System Parent

Updated Date: 2024-05-28 ID: 5a5351cd-ba7e-499e-ad82-2ce160ffa637 Author: Steven Dick Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects any system integrity level process spawned by a non-system account. It leverages Sysmon EventID 1, focusing on process integrity and parent user data. This behavior is significant as it often indicates successful privilege escalation to SYSTEM from a user-controlled process or service. If confirmed malicious, this activity could allow an attacker to gain full control over the system, execute arbitrary code, and potentially compromise the entire environment.

Search

1`sysmon` EventCode=1 IntegrityLevel="system" ParentUser=* NOT ParentUser IN ("*SYSTEM","*LOCAL SERVICE","*NETWORK SERVICE","*DWM-*","*$","-") 
2| eval src_user = replace(ParentUser,"^[^\\\]+\\\\","") 
3| stats count min(_time) as firstTime max(_time) as lastTime values(process_name) as process_name values(process) as process, values(process_path) as process_path, values(process_current_directory) as process_current_directory values(parent_process) as parent_process by dest, user, src_user, parent_process_name, parent_process_guid 
4| `security_content_ctime(firstTime)`  
5| `security_content_ctime(lastTime)` 
6| `windows_privilege_escalation_system_process_without_system_parent_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
CrowdStrike ProcessRollup2	N/A	`'crowdstrike:events:sensor'`	`'crowdstrike'`	N/A

Macros Used

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

windows_privilege_escalation_system_process_without_system_parent_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
T1068	Exploitation for Privilege Escalation	Privilege Escalation
T1548	Abuse Elevation Control Mechanism	Defense Evasion
T1134	Access Token Manipulation	Privilege Escalation

KillChainPhase.EXPLOITAITON

NistCategory.DE_CM

Cis18Value.CIS_10

APT28

APT29

APT32

APT33

BITTER

Cobalt Group

FIN6

FIN8

LAPSUS$

MoustachedBouncer

PLATINUM

Scattered Spider

Threat Group-3390

Tonto Team

Turla

Whitefly

ZIRCONIUM

Blue Mockingbird

FIN6

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

Target environment must ingest sysmon data, specifically Event ID 1 with process integrity and parent user data.

Known False Positives

Unknown

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
The process [$process_name$] on $dest$ was launched with system level integrity by $src_user$.	80	100	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-Sysmon/Operational`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/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: 2