Detection rules › Splunk

Windows Remote Assistance Spawning Process

Status
production
Severity
medium
Group by
IntegrityLevel, command_line, computer_name, event_action, original_file_name, parent_command_line, parent_process_guid, parent_process_id, parent_process_name, process_guid, process_hash, process_id, process_name, user, user_id, vendor_product
Author
Michael Haag, Splunk
Source
github.com/splunk/security_content

The following analytic detects Microsoft Remote Assistance (msra.exe) spawning PowerShell.exe or cmd.exe as a child process. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process creation events where msra.exe is the parent process. This activity is significant because msra.exe typically does not spawn command-line interfaces, indicating potential process injection or misuse. If confirmed malicious, an attacker could use this technique to execute arbitrary commands, escalate privileges, or maintain persistence on the compromised system.

Known false positives

  • False positives should be limited, filter as needed. Add additional shells as needed.

MITRE ATT&CK coverage

TacticTechniques
Privilege Escalation
Stealth

Telemetry coverage

Rule body

name: Windows Remote Assistance Spawning Process
id: ced50492-8849-11ec-9f68-acde48001122
version: 13
creation_date: '2022-02-09'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic detects Microsoft Remote Assistance (msra.exe) spawning PowerShell.exe or cmd.exe as a child process. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process creation events where msra.exe is the parent process. This activity is significant because msra.exe typically does not spawn command-line interfaces, indicating potential process injection or misuse. If confirmed malicious, an attacker could use this technique to execute arbitrary commands, escalate privileges, or maintain persistence on the compromised system.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |-
    | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
      WHERE Processes.parent_process_name=msra.exe `windows_shells`
      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_remote_assistance_spawning_process_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: False positives should be limited, filter as needed. Add additional shells as needed.
references:
    - https://thedfirreport.com/2022/02/07/qbot-likes-to-move-it-move-it/
    - https://app.any.run/tasks/ca1616de-89a1-4afc-a3e4-09d428df2420/
finding:
    title: An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$, generating behavior not common with msra.exe.
    entity:
        field: dest
        type: system
        score: 50
threat_objects:
    - field: parent_process_name
      type: parent_process_name
    - field: process_name
      type: process_name
analytic_story:
    - Unusual Processes
    - Compromised Windows Host
asset_type: Endpoint
mitre_attack_id:
    - T1055
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint

Stages and Predicates

Stage 1: tstats

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
  WHERE Processes.parent_process_name=msra.exe `windows_shells`
  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

Stage 2: search

| `drop_dm_object_name(Processes)`

Stage 3: search

| `security_content_ctime(firstTime)`

Stage 4: search

| `security_content_ctime(lastTime)`

Stage 5: search

| `windows_remote_assistance_spawning_process_filter`

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
Processes.parent_process_nameeq
  • "msra.exe"
field:"parent_process_name" kind:eq
Processes.process_namein
  • "WindowsTerminal.exe"
  • "bash.exe"
  • "cmd.exe" corpus 121 (elastic 92, splunk 29)
  • "cscript.exe" corpus 67 (elastic 65, splunk 2)
  • "mshta.exe" corpus 84 (elastic 79, splunk 5)
  • "powershell.exe" corpus 184 (elastic 140, splunk 44)
  • "powershell_ise.exe" corpus 52 (splunk 29, elastic 23)
  • "pwsh.exe" corpus 77 (elastic 48, splunk 29)
  • "sh.exe"
  • "wscript.exe" corpus 83 (elastic 82, splunk 1)
  • "wt.exe"
field:"process_name" kind:in