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.

MITRE ATT&CK coverage

TacticTechniques
Privilege EscalationT1055 Process Injection
StealthT1055 Process Injection

Event coverage

Rule body splunk

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/
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 ("$dest$") | 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: 7d
      latest_offset: "0"
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
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1055/msra/msra-windows-sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

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

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Processes.parent_process_nameeq
  • "msra.exe"
Processes.process_namein
  • "WindowsTerminal.exe"
  • "bash.exe"
  • "cmd.exe" corpus 77 (elastic 48, splunk 29)
  • "cscript.exe" corpus 25 (elastic 23, splunk 2)
  • "mshta.exe" corpus 31 (elastic 26, splunk 5)
  • "powershell.exe" corpus 104 (elastic 60, splunk 44)
  • "powershell_ise.exe" corpus 50 (splunk 29, elastic 21)
  • "pwsh.exe" corpus 62 (elastic 33, splunk 29)
  • "sh.exe"
  • "wscript.exe" corpus 29 (elastic 28, splunk 1)
  • "wt.exe"