Detection: Windows Privilege Escalation Suspicious Process Elevation

Updated Date: 2024-05-23 ID: 6a80300a-9f8a-4f22-bd3e-09ca577cfdfc Author: Steven Dick Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects when a process running with low or medium integrity from a user account spawns an elevated process with high or system integrity in suspicious locations. This behavior is identified using process execution data from Windows process monitoring or Sysmon EventID 1. This activity is significant as it may indicate a threat actor successfully elevating privileges, which is a common tactic in advanced attacks. If confirmed malicious, this could allow the attacker to execute code with higher privileges, potentially leading to full system compromise and persistent access.

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 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-*","*$") by Processes.dest, Processes.user, Processes.parent_process_guid, Processes.parent_process, Processes.parent_process_name Processes.process_name Processes.process, Processes.process_path, Processes.process_guid, Processes.process_integrity_level, Processes.process_current_directory 
 3| `drop_dm_object_name(Processes)` 
 4| eval join_guid = process_guid, integrity_level = CASE(match(process_integrity_level,"low"),1,match(process_integrity_level,"medium"),2,match(process_integrity_level,"high"),3,match(process_integrity_level,"system"),4,true(),0) 
 5| rename user as src_user, parent_process* as orig_parent_process*, process* as parent_process* 
 6| join max=0 dest join_guid  [
 7| tstats `security_content_summariesonly` count max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.process_integrity_level IN ("system") NOT Processes.user IN ("*SYSTEM","*LOCAL SERVICE","*NETWORK SERVICE","DWM-*","*$")) OR (Processes.process_integrity_level IN ("high","system") AND (Processes.parent_process_path IN ("*\\\\*","*\\Users\\*","*\\Temp\\*","*\\ProgramData\\*") OR Processes.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 
 8| `drop_dm_object_name(Processes)` 
 9| eval elevated_integrity_level = CASE(match(process_integrity_level,"low"),1,match(process_integrity_level,"medium"),2,match(process_integrity_level,"high"),3,match(process_integrity_level,"system"),4,true(),0) 
10| rename parent_process_guid as join_guid ] 
11| where elevated_integrity_level > integrity_level OR user != elevated_user 
12| fields dest, user, src_user, parent_process_name, parent_process, parent_process_path, parent_process_guid, parent_process_integrity_level, parent_process_current_directory, process_name, process, process_path, process_guid, process_integrity_level, process_current_directory, orig_parent_process_name, orig_parent_process, orig_parent_process_guid, firstTime, lastTime, count  
13| `security_content_ctime(firstTime)`  
14| `security_content_ctime(lastTime)` 
15|  `windows_privilege_escalation_suspicious_process_elevation_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_suspicious_process_elevation_filter search *
windows_privilege_escalation_suspicious_process_elevation_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 process execution data sources such as Windows process monitoring and/or Sysmon EID 1.

Known False Positives

False positives may be generated by administrators installing benign applications using run-as/elevation.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
The user $src_user$ launched a process [$parent_process_name$] which spawned a suspicious elevated integrity process [$process_name$]. 40 100 40
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