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detections/endpoint/windows_mshta_execution_in_registry.yml

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+name: Windows Mshta Execution In Registry
+id: e13ceade-b673-4d34-adc4-4d9c01729753
+version: 1
+date: '2022-10-14'
+author: Teoderick Contreras, Splunk
+type: TTP
+datamodel:
+- Endpoint
+description: The following analytic identifies the usage of mshta.exe Windows binary in registry to execute malicious script.
+  This technique was seen in kovter malware where it create several registry entry which is a encoded javascript and will be executed by 
+  another registry containing mshta and javascript activexobject to execute the encoded script using wscript.shell. 
+  This TTP is a good indication of kovter malware or other adversaries or threat actors leveraging fileless detection that survive system reboot.
+search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Registry 
+  where Registry.registry_value_data = "*mshta*" OR Registry.registry_value_data IN ("*javascript:*", "*vbscript:*","*WScript.Shell*")
+  by Registry.registry_key_name Registry.registry_path Registry.registry_value_data Registry.action Registry.dest
+  | `drop_dm_object_name(Registry)` 
+  | `security_content_ctime(firstTime)` 
+  | `security_content_ctime(lastTime)` 
+  | `windows_mshta_execution_in_registry_filter`'
+how_to_implement: To successfully implement this search, you must be ingesting data
+  that records registry activity from your hosts to populate the endpoint data model
+  in the registry node. This is typically populated via endpoint detection-and-response
+  product, such as Carbon Black or endpoint data sources, such as Sysmon. The data
+  used for this search is typically generated via logs that report reads and writes
+  to the registry.
+known_false_positives: unknown
+references:
+- https://redcanary.com/threat-detection-report/techniques/mshta/
+- https://learn.microsoft.com/en-us/microsoft-365/security/intelligence/fileless-threats?view=o365-worldwide
+tags:
+  analytic_story:
+  - Suspicious Windows Registry Activities
+  - Windows Persistence Techniques
+  asset_type: Endpoint
+  cis20:
+  - CIS 3
+  - CIS 5
+  - CIS 16
+  confidence: 90
+  context:
+  - Source:Endpoint
+  - Stage:Persistence
+  dataset:
+  - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1218.005/mshta_in_registry/sysmon3.log
+  impact: 80
+  kill_chain_phases:
+  - Exploitation
+  message: a registry $registry_path$ contains mshta $registry_value_data$ in $dest$
+  mitre_attack_id:
+  - T1218.005
+  nist:
+  - DE.CM
+  observable:
+  - name: dest
+    type: Hostname
+    role:
+    - Victim
+  - name: user
+    type: User
+    role:
+    - Victim
+  product:
+  - Splunk Enterprise
+  - Splunk Enterprise Security
+  - Splunk Cloud
+  required_fields:
+  - _time
+  - Registry.registry_key_name
+  - Registry.registry_path
+  - Registry.dest
+  - Registry.registry_value_data 
+  - Registry.action 
+  risk_score: 72
+  security_domain: endpoint

tests/endpoint/windows_mshta_execution_in_registry.test.yml

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+name: Windows Mshta Execution In Registry Unit Test
+tests:
+- name: Windows Mshta Execution In Registry
+  file: endpoint/windows_mshta_execution_in_registry.yml
+  pass_condition: '| stats count | where count > 0'
+  earliest_time: -24h
+  latest_time: now
+  attack_data:
+  - file_name: sysmon3.log
+    data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1218.005/mshta_in_registry/sysmon3.log
+    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
+    sourcetype: xmlwineventlog
+    update_timestamp: true