Suspicious Copy on System32

name: Suspicious Copy on System32
id: ce633e56-25b2-11ec-9e76-acde48001122
version: 14
date: '2026-03-10'
author: Teoderick Contreras, Nasreddine Bencherchali, Splunk
status: production
type: Anomaly
description: |
    The following analytic detects potentially suspicious file copy operations targeting the
    System32 or SysWow64 directories as source, often indicative of malicious activity.
    It leverages data from Endpoint Detection and Response (EDR) agents,
    focusing on activity initiated by command-line tools like cmd.exe or PowerShell.
    This behavior is significant as it may indicate an attempt to evade defenses by copying
    an existing binary from the system directory and renaming it.
    If confirmed malicious, this activity could allow an attacker to execute
    code undetected and potentially leading to system compromise or further lateral movement
    within the network.
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 IN (
      "cmd.exe",
      "powershell.exe",
      "pwsh.exe",
      "sqlps.exe",
      "sqltoolsps.exe"
    )
    (
      Processes.process_name IN ("copy.exe", "xcopy.exe")
      OR
      Processes.original_file_name IN ("copy.exe", "xcopy.exe")
    )
    Processes.process IN (
      "* \"C:\\Windows\\System32\\*",
      "* \'C:\\Windows\\System32\\*",
      "* C:\\Windows\\System32\\*",
      "* \"C:\\Windows\\SysWow64\\*",
      "* \'C:\\Windows\\SysWow64\\*",
      "* C:\\Windows\\SysWow64\\*"
    )
    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)`
    | `suspicious_copy_on_system32_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: Copying files from System directories can happen for multiple admin reasons, allbeit rare without approval. Apply additional filters where needed.
references:
    - https://www.hybrid-analysis.com/sample/8da5b75b6380a41eee3a399c43dfe0d99eeefaa1fd21027a07b1ecaa4cd96fdd?environmentId=120
    - https://www.microsoft.com/en-us/security/blog/2023/05/24/volt-typhoon-targets-us-critical-infrastructure-with-living-off-the-land-techniques/
drilldown_searches:
    - name: View the detection results for - "$dest$" and "$user$"
      search: '%original_detection_search% | search  dest = "$dest$" user = "$user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$" and "$user$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$", "$user$") 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: Execution of copy exe to copy file from $process$ on $dest$
    risk_objects:
        - field: dest
          type: system
          score: 20
        - field: user
          type: user
          score: 20
    threat_objects: []
tags:
    analytic_story:
        - Qakbot
        - Sandworm Tools
        - IcedID
        - Volt Typhoon
        - AsyncRAT
        - Unusual Processes
        - Compromised Windows Host
        - Water Gamayun
    asset_type: Endpoint
    mitre_attack_id:
        - T1036.003
    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/T1036.003/copy_sysmon/sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog