Detection rules › Sigma
Cscript/Wscript Uncommon Script Extension Execution
Detects Wscript/Cscript executing a file with an uncommon (i.e. non-script) extension
MITRE ATT&CK coverage
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 1: Process creation |
Rule body
title: Cscript/Wscript Uncommon Script Extension Execution
id: 99b7460d-c9f1-40d7-a316-1f36f61d52ee
status: test
description: Detects Wscript/Cscript executing a file with an uncommon (i.e. non-script) extension
references:
- Internal Research
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-05-15
modified: 2023-06-19
tags:
- attack.execution
- attack.t1059.005
- attack.t1059.007
logsource:
category: process_creation
product: windows
detection:
selection_img:
- OriginalFileName:
- 'wscript.exe'
- 'cscript.exe'
- Image|endswith:
- '\wscript.exe'
- '\cscript.exe'
selection_extension:
CommandLine|contains:
# Note: add additional potential suspicious extension
# We could specify the "//E:" flag to avoid typos by admin. But since that's prone to blind spots via the creation of assoc it's better not to include it
- '.csv'
- '.dat'
- '.doc'
- '.gif'
- '.jpeg'
- '.jpg'
- '.png'
- '.ppt'
- '.txt'
- '.xls'
- '.xml'
condition: all of selection_*
falsepositives:
- Unknown
level: high
Stages and Predicates
Stage 0: condition
all of selection_*Stage 1: selection_img
selection_img:
- OriginalFileName:
- 'wscript.exe'
- 'cscript.exe'
- Image|endswith:
- '\wscript.exe'
- '\cscript.exe'
Stage 2: selection_extension
selection_extension:
CommandLine|contains:
- '.csv'
- '.dat'
- '.doc'
- '.gif'
- '.jpeg'
- '.jpg'
- '.png'
- '.ppt'
- '.txt'
- '.xls'
- '.xml'
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
CommandLine | match |
| field:"CommandLine" kind:match |
Image | ends_with |
| field:"Image" kind:ends_with |
OriginalFileName | eq |
| field:"OriginalFileName" kind:eq |