Windows DotNet Binary in Non Standard Path

name: Windows DotNet Binary in Non Standard Path
id: fddf3b56-7933-11ec-98a6-acde48001122
version: 14
creation_date: '2022-01-20'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
description: |
    The following analytic detects the execution of native .NET binaries from non-standard directories within the Windows operating system.
    It leverages Endpoint Detection and Response (EDR) telemetry, comparing process names and original file names against a predefined lookup "is_net_windows_file".
    This activity is significant because adversaries may move .NET binaries to unconventional paths to evade detection and execute malicious code.
    If confirmed malicious, this behavior could allow attackers to execute arbitrary code, escalate privileges, or maintain persistence within the environment, posing a significant security risk.
    Also this analytic leverages a sub-search to enhance performance. sub-searches have limitations on the amount of data they can return. Keep this in mind if you have an extensive list of ransomware note file names.
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
    NOT Processes.process_path IN (
          "*:\\Windows\\ADWS\\*",
          "*:\\Windows\\Microsoft.NET\\*",
          "*:\\Windows\\NetworkController\\*",
          "*:\\Windows\\System32\\*",
          "*:\\Windows\\SystemApps\\*",
          "*:\\Windows\\SysWOW64\\*",
          "*:\\Windows\\WinSxS\\*"
        )
    (
      [ | inputlookup is_net_windows_file
        | search netFile=true
        | fields originalFileName
        | rename originalFileName as Processes.original_file_name
        | format
      ]
    )
    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)`
    | lookup update=true is_net_windows_file filename as process_name OUTPUT netFile
    | lookup update=true is_net_windows_file originalFileName as original_file_name OUTPUT netFile
    | search netFile=true
    | `windows_dotnet_binary_in_non_standard_path_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 may be present and filtering may be required. Certain utilities will run from non-standard paths based on the third-party application in use.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1036.003/T1036.003.yaml
    - https://attack.mitre.org/techniques/T1036/003/
    - https://www.microsoft.com/security/blog/2022/01/15/destructive-malware-targeting-ukrainian-organizations/
    - https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1218.004/T1218.004.md
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 ("$user$", "$dest$") | 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 $process_name$ from a non-standard path was identified on endpoint $dest$ by user $user$.
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: An instance of $parent_process_name$ spawning $process_name$ from a non-standard path was identified on endpoint $dest$ by user $user$.
threat_objects:
    - field: parent_process_name
      type: parent_process_name
    - field: process_name
      type: process_name
analytic_story:
    - Masquerading - Rename System Utilities
    - Ransomware
    - Unusual Processes
    - Signed Binary Proxy Execution InstallUtil
    - Data Destruction
    - WhisperGate
asset_type: Endpoint
mitre_attack_id:
    - T1036.003
    - T1218.004
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/T1218.004/atomic_red_team/windows-sysmon_installutil_path.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit