Detection: Windows Privilege Escalation System Process Without System Parent

Updated Date: 2024-11-13 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.

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
CrowdStrike ProcessRollup2 N/A 'crowdstrike:events:sensor' 'crowdstrike'
Sysmon EventID 1 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'
Windows Event Log Security 4688 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Security'

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
Exploitation
DE.CM
CIS 10

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:

The process [$process_name$] on $dest$ was launched with system level integrity by $src_user$.

Risk Object Risk Object Type Risk Score Threat Objects
src_user user 80 process_name
dest system 80 process_name

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: 4