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Windows Indirect Command Execution Via pcalua

The following analytic detects programs initiated by pcalua.exe, the Microsoft Windows Program Compatibility Assistant. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process and parent process information. While pcalua.exe can start legitimate programs, it is significant because attackers may use it to bypass command line execution protections. If confirmed malicious, this activity could allow attackers to execute arbitrary commands, potentially leading to unauthorized actions, privilege escalation, or persistence within the environment.

MITRE ATT&CK

T1202

Detection Query

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
  WHERE Processes.parent_process="*pcalua* -a*"
  BY Processes.action Processes.dest Processes.original_file_name
     Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
     Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
     Processes.process Processes.process_exec Processes.process_guid
     Processes.process_hash Processes.process_id Processes.process_integrity_level
     Processes.process_name Processes.process_path Processes.user
     Processes.user_id Processes.vendor_product
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_indirect_command_execution_via_pcalua_filter`

Author

Eric McGinnis, Splunk

Created

2026-03-10

Data Sources

Sysmon EventID 1CrowdStrike ProcessRollup2

References

Tags

Living Off The Land

Raw Content

name: Windows Indirect Command Execution Via pcalua
id: 3428ac18-a410-4823-816c-ce697d26f7a8
version: 9
date: '2026-03-10'
author: Eric McGinnis, Splunk
status: production
type: TTP
description: The following analytic detects programs initiated by pcalua.exe, the Microsoft Windows Program Compatibility Assistant. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process and parent process information. While pcalua.exe can start legitimate programs, it is significant because attackers may use it to bypass command line execution protections. If confirmed malicious, this activity could allow attackers to execute arbitrary commands, potentially leading to unauthorized actions, privilege escalation, or persistence within the environment.
data_source:
    - Sysmon EventID 1
    - CrowdStrike ProcessRollup2
search: |-
    | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
      WHERE Processes.parent_process="*pcalua* -a*"
      BY Processes.action Processes.dest Processes.original_file_name
         Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
         Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
         Processes.process Processes.process_exec Processes.process_guid
         Processes.process_hash Processes.process_id Processes.process_integrity_level
         Processes.process_name Processes.process_path Processes.user
         Processes.user_id Processes.vendor_product
    | `drop_dm_object_name(Processes)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `windows_indirect_command_execution_via_pcalua_filter`
how_to_implement: The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
known_false_positives: Some legacy applications may be run using pcalua.exe.  Filter these results as needed.
references:
    - https://twitter.com/KyleHanslovan/status/912659279806640128
    - https://lolbas-project.github.io/lolbas/Binaries/Pcalua/
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") starthoursago=168  | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
rba:
    message: The Program Compatability Assistant (pcalua.exe) launched the process $process_name$
    risk_objects:
        - field: dest
          type: system
          score: 50
    threat_objects: []
tags:
    analytic_story:
        - Living Off The Land
    asset_type: Endpoint
    mitre_attack_id:
        - T1202
    product:
        - Splunk Enterprise
        - Splunk Enterprise Security
        - Splunk Cloud
    security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1202/atomic_red_team/windows-sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog