Detection rules › Splunk

Windows System Time Discovery W32tm Delay

Status
production
Severity
low
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
Teoderick Contreras, Splunk
Source
github.com/splunk/security_content

The following analytic identifies the use of the w32tm.exe utility with the /stripchart function, which is indicative of DCRat malware delaying its payload execution. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on specific command-line arguments used by w32tm.exe. This activity is significant as it may indicate an attempt to evade detection by delaying malicious actions such as C2 communication and beaconing. If confirmed malicious, this behavior could allow an attacker to maintain persistence and execute further malicious activities undetected.

Known false positives

  • No false positives have been identified at this time.

MITRE ATT&CK coverage

TacticTechniques
Discovery

Telemetry coverage

Rule body

name: Windows System Time Discovery W32tm Delay
id: b2cc69e7-11ba-42dc-a269-59c069a48870
version: 11
creation_date: '2022-07-27'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic identifies the use of the w32tm.exe utility with the /stripchart function, which is indicative of DCRat malware delaying its payload execution. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on specific command-line arguments used by w32tm.exe. This activity is significant as it may indicate an attempt to evade detection by delaying malicious actions such as C2 communication and beaconing. If confirmed malicious, this behavior could allow an attacker to maintain persistence and execute further malicious activities undetected.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |-
    | tstats `security_content_summariesonly` values(Processes.process) as process min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
      WHERE Processes.process_name = w32tm.exe Processes.process= "* /stripchart *" Processes.process= "* /computer:localhost *" Processes.process= "* /period:*" Processes.process= "* /dataonly *" Processes.process= "* /samples:*"
      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_system_time_discovery_w32tm_delay_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: No false positives have been identified at this time.
references:
    - https://cert.gov.ua/article/405538
    - https://malpedia.caad.fkie.fraunhofer.de/details/win.dcrat
    - https://www.mandiant.com/resources/analyzing-dark-crystal-rat-backdoor
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 20
          message: Process name w32tm.exe is using suspcicious command line arguments $process$ on host $dest$.
analytic_story:
    - DarkCrystal RAT
asset_type: Endpoint
mitre_attack_id:
    - T1124
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint

Stages and Predicates

Stage 1: tstats

| tstats `security_content_summariesonly` values(Processes.process) as process min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
  WHERE Processes.process_name = w32tm.exe Processes.process= "* /stripchart *" Processes.process= "* /computer:localhost *" Processes.process= "* /period:*" Processes.process= "* /dataonly *" Processes.process= "* /samples:*"
  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_system_time_discovery_w32tm_delay_filter`

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
Processes.processeq
  • "* /computer:localhost *"
  • "* /dataonly *"
  • "* /period:*"
  • "* /samples:*"
  • "* /stripchart *"
field:"CommandLine" kind:eq
Processes.process_nameeq
  • "w32tm.exe" corpus 3 (elastic 2, splunk 1)
field:"process_name" kind:eq