Detection rules › Sigma
WinSxS Executable File Creation By Non-System Process
Detects the creation of binaries in the WinSxS folder by non-system processes
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution | No specific technique |
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 11: FileCreate |
Rule body
title: WinSxS Executable File Creation By Non-System Process
id: 34746e8c-5fb8-415a-b135-0abc167e912a
related:
- id: 64827580-e4c3-4c64-97eb-c72325d45399
type: derived
status: test
description: Detects the creation of binaries in the WinSxS folder by non-system processes
references:
- https://media.defense.gov/2023/May/09/2003218554/-1/-1/0/JOINT_CSA_HUNTING_RU_INTEL_SNAKE_MALWARE_20230509.PDF
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-05-11
tags:
- attack.execution
logsource:
category: file_event
product: windows
detection:
selection:
TargetFilename|startswith: 'C:\Windows\WinSxS\'
TargetFilename|endswith: '.exe'
filter_main_system_location:
Image|startswith:
- 'C:\Windows\Systems32\'
- 'C:\Windows\SysWOW64\'
- 'C:\Windows\WinSxS\'
condition: selection and not 1 of filter_main_*
falsepositives:
- Unknown
level: medium
Stages and Predicates
Stage 0: condition
selection and not 1 of filter_main_*Stage 1: selection
selection:
TargetFilename|startswith: 'C:\Windows\WinSxS\'
TargetFilename|endswith: '.exe'
Stage 2: not filter_main_system_location
filter_main_system_location:
Image|startswith:
- 'C:\Windows\Systems32\'
- 'C:\Windows\SysWOW64\'
- 'C:\Windows\WinSxS\'
Exclusions
The rule actively suppresses these predicates.
| Field | Kind | Excluded values | Search |
|---|---|---|---|
Image | starts_with | C:\Windows\SysWOW64\ | excludes:Image field:"Image" value:"C:\Windows\SysWOW64\" |
Image | starts_with | C:\Windows\Systems32\ | excludes:Image field:"Image" value:"C:\Windows\Systems32\" |
Image | starts_with | C:\Windows\WinSxS\ | excludes:Image field:"Image" value:"C:\Windows\WinSxS\" |
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
TargetFilename | ends_with |
| field:"TargetFilename" kind:ends_with value:".exe" |
TargetFilename | starts_with |
| field:"TargetFilename" kind:starts_with value:"C:\Windows\WinSxS\" |