mirror of
https://github.com/splunk/security_content
synced 2026-06-08 17:32:49 +00:00
Eric McGinnis
78 lines
3.9 KiB
YAML
78 lines
3.9 KiB
YAML
name: Windows PowerShell Module File Created
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id: ef018634-8999-4854-9344-bde9593468e7
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version: 2
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creation_date: '2021-09-02'
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modification_date: '2026-05-13'
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author: Raven Tait, Splunk
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status: production
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type: Anomaly
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description: |-
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Detects the creation of a DLL within the various PowerShell module directories.
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This can indicate a new module being installed, attempts at ScriptBlock smuggling, or other malicious PowerShell activity utilizing modules.
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False positives could include installation of legitimate modules.
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data_source:
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- Sysmon EventID 11
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search: |-
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| tstats `security_content_summariesonly`
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count min(_time) as firstTime
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max(_time) as lastTime
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from datamodel=Endpoint.Filesystem where
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Filesystem.action="created"
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Filesystem.file_path="*\\WindowsPowerShell\\Modules\\*.dll"
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Filesystem.file_name="*.dll"
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by Filesystem.dest Filesystem.file_create_time Filesystem.process_path
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Filesystem.process_guid Filesystem.process_id Filesystem.file_path Filesystem.file_name
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Filesystem.user Filesystem.vendor_product Filesystem.action
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| `drop_dm_object_name(Filesystem)`
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| `security_content_ctime(firstTime)`
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| `security_content_ctime(lastTime)`
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| `windows_powershell_module_file_created_filter`
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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.
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known_false_positives: Legitimate installation of approved PowerShell modules may trigger this detection. Verify module sources to reduce false positives.
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references:
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- https://bc-security.org/scriptblock-smuggling/
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- https://github.com/BC-SECURITY/ScriptBlock-Smuggling
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drilldown_searches:
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- earliest_offset: $info_min_time$
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latest_offset: $info_max_time$
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name: View the detection results for - "$user$" and "$dest$"
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search: '%original_detection_search% | search user = "$user$" dest = "$dest$"'
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- name: View risk events for the last 7 days for - "$user$" and "$dest$"
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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)`'
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earliest_offset: 7d
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latest_offset: "0"
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intermediate_findings:
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entities:
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- field: dest
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type: system
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score: 20
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message: PowerShell module DLL created at $file_path$ on $dest$.
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threat_objects:
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- field: file_path
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type: file_path
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analytic_story:
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- Malicious PowerShell
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- Windows Persistence Techniques
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asset_type: Endpoint
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mitre_attack_id:
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- T1129
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- T1059.001
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- T1574
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product:
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- Splunk Enterprise
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- Splunk Enterprise Security
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- Splunk Cloud
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category: endpoint
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security_domain: endpoint
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tests:
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- name: True Positive Test
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attack_data:
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- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1129/snapattack/snapattack.log
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source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
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sourcetype: XmlWinEventLog
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test_type: unit
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