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splunk-security_content/detections/endpoint/script_execution_via_wmi.yml
2024-10-30 18:42:30 -07:00

62 lines
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YAML

name: Script Execution via WMI
id: aa73f80d-d728-4077-b226-81ea0c8be589
version: 6
date: '2024-09-30'
author: Rico Valdez, Michael Haag, Splunk
status: production
type: TTP
description: The following analytic detects the execution of scripts via Windows Management Instrumentation (WMI) by monitoring the process 'scrcons.exe'. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process creation events. WMI-based script execution is significant because adversaries often use it to perform malicious activities stealthily, such as system compromise, data exfiltration, or establishing persistence. If confirmed malicious, this activity could allow attackers to execute arbitrary code, escalate privileges, or maintain long-term access to the environment. Analysts should differentiate between legitimate administrative use and potential threats.
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.process_name=scrcons.exe by Processes.dest Processes.user Processes.parent_process Processes.process_name Processes.process Processes.process_id Processes.parent_process_id | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `script_execution_via_wmi_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: Although unlikely, administrators may use wmi to launch scripts for legitimate purposes. Filter as needed.
references:
- https://redcanary.com/blog/child-processes/
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: $info_max_time$
tags:
analytic_story:
- Suspicious WMI Use
asset_type: Endpoint
confidence: 60
impact: 60
message: A wmic.exe process $process_name$ that execute script in host $dest$
mitre_attack_id:
- T1047
observable:
- name: dest
type: Hostname
role:
- Victim
- name: user
type: User
role:
- Victim
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
required_fields:
- _time
- Processes.process_name
- Processes.user
- Processes.dest
risk_score: 36
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1047/execution_scrcons/windows-sysmon.log
source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
sourcetype: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational