Excel WSH

detections/endpoint/excel_spawning_windows_script_host.yml

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+name: Excel Spawning Windows Script Host
+id: 57fe880a-9be3-11eb-9bf3-acde48001122
+version: 1
+date: '2021-04-12'
+author: Michael Haag, Splunk
+type: batch
+datamodel:
+- Endpoint
+description: The following detection identifies Microsoft Excel spawning Windows Script Host - `cscript.exe` or `wscript.exe`.
+  Typically, this is not common behavior and not default with Excel.exe. Excel.exe
+  will generally be found in the following path `C:\Program Files\Microsoft Office\root\Office16`
+  (version will vary). `cscript.exe` or `wscript.exe` default location is `c:\windows\system32\` or c:windows\syswow64`. `cscript.exe` or `wscript.exe` spawning from Excel.exe is common for a spearphishing
+  attachment and is actively used. Albeit, the command-line executed will most likely be
+  obfuscated and captured via another detection. During triage, review parallel processes
+  and identify any files that may have been written. Review the reputation of the remote destination and block accordingly.
+search: '| tstats `security_content_summariesonly` count values(Processes.process)
+  min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes
+  where Processes.parent_process_name="excel.exe" Processes.process_name IN ("cscript.exe", "wscript.exe")  by Processes.parent_process Processes.process_name
+  Processes.user Processes.dest | `drop_dm_object_name("Processes")` | `security_content_ctime(firstTime)`|`security_content_ctime(lastTime)` | `excel_spawning_windows_script_host_filter`'
+how_to_implement: To successfully implement this search you need to be ingesting information
+  on process that include the name of the process responsible for the changes from
+  your endpoints into the `Endpoint` datamodel in the `Processes` node.
+known_false_positives: False positives should be limited, but if any are present,
+  filter as needed. In some instances, `cscript.exe` is used for legitimate business practices.
+references:
+- https://app.any.run/tasks/8ecfbc29-03d0-421c-a5bf-3905d29192a2/
+- https://attack.mitre.org/techniques/T1566/001/
+tags:
+  analytic_story:
+  - Spearphishing Attachments
+  dataset: []
+  kill_chain_phases:
+  - Exploitation
+  mitre_attack_id:
+  - T1003.002
+  product:
+  - Splunk Enterprise
+  - Splunk Enterprise Security
+  - Splunk Cloud
+  required_fields:
+  - _time
+  - process_name
+  - process_id
+  - parent_process_name
+  - dest
+  - user
+  - parent_process_id
+  security_domain: endpoint

tests/endpoint/excel_spawning_windows_script_host.test.yml

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+name: Excel Spawning Windows Script Host Unit Test
+tests:
+- name: Excel Spawning Windows Script Host
+  file: endpoint/excel_spawning_windows_script_host.yml
+  pass_condition: '| stats count | where count > 0'
+  earliest_time: '-24h'
+  latest_time: 'now'
+  attack_data:
+  - file_name: windows-sysmon.log
+    data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1566.001/macro/windows-sysmon.log
+    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
+    sourcetype: xmlwineventlog