Detection rules › Splunk

Windows NetSupport RMM DLL Loaded By Uncommon Process

Status
production
Severity
low
Group by
dest, image_loaded, original_file_name, process_guid, process_hash, process_id, process_name, service_dll_signature_exists, service_dll_signature_verified, signature, signature_id, user_id, vendor_product
Author
Teoderick Contreras, Splunk
Source
github.com/splunk/security_content

The following analytic detects the loading of specific dynamic-link libraries (DLLs) associated with the NetSupport Remote Manager (RMM) tool by any process on a Windows system. Modules such as CryptPak.dll, HTCTL32.DLL, IPCTL32.DLL, keyshowhook.dll, pcicapi.DLL, PCICL32.DLL, and TCCTL32.DLL, are integral to NetSupport's functionality. This detection is particularly valuable when these modules are loaded by processes running from unusual directories (e.g., Downloads, ProgramData, or user-specific folders) rather than the legitimate Program Files installation path, or by executables that have been renamed but retain the internal "client32" identifier. This helps to identify instances where the legitimate NetSupport tool is being misused by adversaries as a Remote Access Trojan (RAT).

Known false positives

  • NetSupport RMM installations outside of the standard Program Files directory will trigger this detection. Apply appropriate filters to exclude known legitimate installations.

MITRE ATT&CK coverage

TacticTechniques
Stealth

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 7: Image loaded

Rule body

name: Windows NetSupport RMM DLL Loaded By Uncommon Process
id: 125f96f9-6f34-418b-b868-c4a8d7fb865f
version: 4
creation_date: '2025-11-21'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: |
    The following analytic detects the loading of specific dynamic-link libraries (DLLs) associated with the NetSupport Remote Manager (RMM) tool by any process on a Windows system.
    Modules such as CryptPak.dll, HTCTL32.DLL, IPCTL32.DLL, keyshowhook.dll, pcicapi.DLL, PCICL32.DLL, and TCCTL32.DLL, are integral to NetSupport's functionality.
    This detection is particularly valuable when these modules are loaded by processes running from unusual directories (e.g., Downloads, ProgramData, or user-specific folders) rather than the legitimate Program Files installation path, or by executables that have been renamed but retain the internal "client32" identifier.
    This helps to identify instances where the legitimate NetSupport tool is being misused by adversaries as a Remote Access Trojan (RAT).
data_source:
    - Sysmon EventID 7
search: |
    `sysmon`
    EventCode=7
    ImageLoaded IN (
      "*\\CryptPak.dll",
      "*\\HTCTL32.DLL",
      "*\\pcicapi.dll",
      "*\\pcichek.dll",
      "*\\PCICL32.DLL",
      "*\\TCCTL32.DLL"
    )
    NOT Image IN ("C:\\Program Files\\*", "C:\\Program Files (x86)\\*")
    Signature = "NetSupport Ltd*"
    | fillnull
    | stats count min(_time) as firstTime max(_time) as lastTime
      by Image ImageLoaded dest loaded_file loaded_file_path original_file_name process_exec
         process_guid process_hash process_id process_name process_path service_dll_signature_exists
         service_dll_signature_verified signature signature_id user_id vendor_product
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `windows_netsupport_rmm_dll_loaded_by_uncommon_process_filter`
how_to_implement: |
    To successfully implement this search, you need to be ingesting logs with the process name and ImageLoaded executions from your endpoints.
    If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.
known_false_positives: |
    NetSupport RMM installations outside of the standard Program Files directory will trigger this detection.
    Apply appropriate filters to exclude known legitimate installations.
references:
    - https://www.linkedin.com/posts/mauricefielenbach_cybersecurity-incidentresponse-dfir-activity-7394805779448418304-g0gZ?utm_source=share&utm_medium=member_desktop&rcm=ACoAAAuFTjIB5weY_kcyu4qp3kHbI4v49tO0zEk
    - https://thedfirreport.com/2023/10/30/netsupport-intrusion-results-in-domain-compromise/
    - https://www.esentire.com/blog/evalusion-campaign-delivers-amatera-stealer-and-netsupport-rat
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 20
          message: The following module $ImageLoaded$ was loaded by a non-standard application on endpoint $dest$
threat_objects:
    - field: Image
      type: process_name
analytic_story:
    - NetSupport RMM Tool Abuse
asset_type: Endpoint
mitre_attack_id:
    - T1036
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint

Stages and Predicates

Stage 1: search

`sysmon`
EventCode=7
ImageLoaded IN (
  "*\\CryptPak.dll",
  "*\\HTCTL32.DLL",
  "*\\pcicapi.dll",
  "*\\pcichek.dll",
  "*\\PCICL32.DLL",
  "*\\TCCTL32.DLL"
)
NOT Image IN ("C:\\Program Files\\*", "C:\\Program Files (x86)\\*")
Signature = "NetSupport Ltd*"

Stage 2: fillnull

| fillnull

Stage 3: stats

| stats count min(_time) as firstTime max(_time) as lastTime
  by Image ImageLoaded dest loaded_file loaded_file_path original_file_name process_exec
     process_guid process_hash process_id process_name process_path service_dll_signature_exists
     service_dll_signature_verified signature signature_id user_id vendor_product

Stage 4: search

| `security_content_ctime(firstTime)`

Stage 5: search

| `security_content_ctime(lastTime)`

Stage 6: search

| `windows_netsupport_rmm_dll_loaded_by_uncommon_process_filter`

Exclusions

The rule actively suppresses these predicates.

FieldKindExcluded valuesSearch
Imagein"C:\\Program Files (x86)\\*", "C:\\Program Files\\*"excludes:Image

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
EventCodeeq
  • 7 corpus 41 (splunk 39, elastic 1, kusto 1)
field:"EventID" kind:eq value:"7"
ImageLoadedin
  • "*\\CryptPak.dll"
  • "*\\HTCTL32.DLL"
  • "*\\PCICL32.DLL"
  • "*\\TCCTL32.DLL"
  • "*\\pcicapi.dll"
  • "*\\pcichek.dll"
field:"ImageLoaded" kind:in
Signatureeq
  • "NetSupport Ltd*"
field:"Signature" kind:eq