Detection: Windows Privilege Escalation User Process Spawn System Process

Updated Date: 2024-05-13 ID: c9687a28-39ad-43c6-8bcf-eaf061ba0cbe Author: Steven Dick Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects when a process with low, medium, or high integrity spawns a system integrity process from a user-controlled location. This behavior is indicative of privilege escalation attempts where attackers elevate their privileges to SYSTEM level from a user-controlled process or service. The detection leverages Sysmon data, specifically Event ID 15, to identify such transitions. Monitoring this activity is crucial as it can signify an attacker gaining SYSTEM-level access, potentially leading to full control over the affected system, unauthorized access to sensitive data, and further malicious activities.

 1
 2| tstats `security_content_summariesonly` count min(_time) as firstTime from datamodel=Endpoint.Processes where Processes.process_integrity_level IN ("low","medium","high") NOT Processes.user IN ("*SYSTEM","*LOCAL SERVICE","*NETWORK SERVICE","DWM-*","*$") AND Processes.process_path IN ("*\\\\*","*\\Users\\*","*\\Temp\\*","*\\ProgramData\\*") by Processes.dest, Processes.user, Processes.parent_process_guid, Processes.parent_process, Processes.parent_process_name Processes.process_name Processes.process, Processes.process_path, Processes.process_guid, Processes.process_integrity_level, Processes.process_current_directory 
 3| `drop_dm_object_name(Processes)` 
 4| eval join_guid = process_guid 
 5| join max=0 dest join_guid  [
 6| tstats `security_content_summariesonly` count max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_integrity_level IN ("system") AND Processes.parent_process_path IN ("*\\\\*","*\\Users\\*","*\\Temp\\*","*\\ProgramData\\*") by Processes.dest, Processes.user, Processes.parent_process_guid, Processes.process_name, Processes.process, Processes.process_path, Processes.process_integrity_level, Processes.process_current_directory 
 7| `drop_dm_object_name(Processes)` 
 8| rename parent_process_guid as join_guid, process* as system_process*, user as system_user ] 
 9| fields dest, user, parent_process, parent_process_name, parent_process_guid, process, process_name, process_guid, process_integrity_level,process_path, process_current_directory, system_process_name, system_process, system_process_path, system_process_integrity_level, system_process_current_directory, system_user, firstTime, lastTime, count 
10| `security_content_ctime(firstTime)`  
11| `security_content_ctime(lastTime)` 
12| `windows_privilege_escalation_user_process_spawn_system_process_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_user_process_spawn_system_process_filter search *
windows_privilege_escalation_user_process_spawn_system_process_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 15.

Known False Positives

Unknown

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
The user $user$ launched a process [$process_name$] which spawned a system level integrity process [$system_process$]. 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