Suspicious Reg exe Process

name: Suspicious Reg exe Process
id: a6b3ab4e-dd77-4213-95fa-fc94701995e0
version: 14
date: '2026-03-10'
author: David Dorsey, Splunk
status: production
type: Anomaly
description: The following analytic identifies instances of reg.exe being launched from a command prompt (cmd.exe) that was not initiated by the user, as indicated by a parent process other than explorer.exe. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process and parent process names. This activity is significant because reg.exe is often used in registry manipulation, which can be indicative of malicious behavior such as persistence mechanisms or system configuration changes. If confirmed malicious, this could allow an attacker to modify critical system settings, potentially leading to privilege escalation or persistent access.
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 != explorer.exe Processes.process_name =cmd.exe
      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)`
    | search [
    | tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes
      WHERE Processes.parent_process_name=cmd.exe Processes.process_name= reg.exe
      BY Processes.parent_process_id Processes.dest Processes.process_name
    | `drop_dm_object_name("Processes")`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | rename parent_process_id as process_id
    | dedup process_id
    | table process_id dest]
    | `suspicious_reg_exe_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: It's possible for system administrators to write scripts that exhibit this behavior. If this is the case, the search will need to be modified to filter them out.
references:
    - https://car.mitre.org/wiki/CAR-2013-03-001/
drilldown_searches:
    - name: View the detection results for - "$user$" and "$dest$"
      search: '%original_detection_search% | search  user = "$user$" dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$user$" and "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") 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: An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$ attempting to add a registry entry.
    risk_objects:
        - field: user
          type: user
          score: 20
        - field: dest
          type: system
          score: 20
    threat_objects:
        - field: parent_process_name
          type: parent_process_name
        - field: process_name
          type: process_name
tags:
    analytic_story:
        - Windows Defense Evasion Tactics
        - Disabling Security Tools
        - DHS Report TA18-074A
    asset_type: Endpoint
    mitre_attack_id:
        - T1112
    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/T1112/atomic_red_team/windows-sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog