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splunk-security_content/detections/endpoint/excel_spawning_windows_script_host.yml
2021-04-22 21:55:11 +00:00

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YAML

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
automated_detection_testing: passed
dataset:
- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1566.001/macro/windows-sysmon.log
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