Detection rules › Sigma
Suspicious Process Parents
Detects suspicious parent processes that should not have any children or should only have a single possible child program
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth |
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 1: Process creation |
| Security-Auditing | Event ID 4688: A new process has been created. |
Rule body
title: Suspicious Process Parents
id: cbec226f-63d9-4eca-9f52-dfb6652f24df
status: test
description: Detects suspicious parent processes that should not have any children or should only have a single possible child program
references:
- https://twitter.com/x86matthew/status/1505476263464607744?s=12
- https://svch0st.medium.com/stats-from-hunting-cobalt-strike-beacons-c17e56255f9b
author: Florian Roth (Nextron Systems)
date: 2022-03-21
modified: 2022-09-08
tags:
- attack.stealth
- attack.t1036
logsource:
category: process_creation
product: windows
detection:
selection:
ParentImage|endswith:
- '\minesweeper.exe'
- '\winver.exe'
- '\bitsadmin.exe'
selection_special:
ParentImage|endswith:
- '\csrss.exe'
- '\certutil.exe'
# - '\schtasks.exe'
- '\eventvwr.exe'
- '\calc.exe'
- '\notepad.exe'
filter_special:
Image|endswith:
- '\WerFault.exe'
- '\wermgr.exe'
- '\conhost.exe' # csrss.exe, certutil.exe
- '\mmc.exe' # eventvwr.exe
- '\win32calc.exe' # calc.exe
- '\notepad.exe'
filter_null:
Image: null
condition: selection or ( selection_special and not 1 of filter_* )
falsepositives:
- Unknown
level: high
Stages and Predicates
Stage 0: condition
selection or ( selection_special and not 1 of filter_* )Stage 1: selection
selection:
ParentImage|endswith:
- '\minesweeper.exe'
- '\winver.exe'
- '\bitsadmin.exe'
Stage 2: selection_special
selection_special:
ParentImage|endswith:
- '\csrss.exe'
- '\certutil.exe'
- '\eventvwr.exe'
- '\calc.exe'
- '\notepad.exe'
Stage 3: not filter_*
filter_special:
Image|endswith:
- '\WerFault.exe'
- '\wermgr.exe'
- '\conhost.exe'
- '\mmc.exe'
- '\win32calc.exe'
- '\notepad.exe'
filter_null:
Image: null
Exclusions
The rule actively suppresses these predicates.
| Field | Kind | Excluded values | Search |
|---|---|---|---|
Image | ends_with | \WerFault.exe | excludes:Image field:"Image" value:"\WerFault.exe" |
Image | ends_with | \conhost.exe | excludes:Image field:"Image" value:"\conhost.exe" |
Image | ends_with | \mmc.exe | excludes:Image field:"Image" value:"\mmc.exe" |
Image | ends_with | \notepad.exe | excludes:Image field:"Image" value:"\notepad.exe" |
Image | ends_with | \wermgr.exe | excludes:Image field:"Image" value:"\wermgr.exe" |
Image | ends_with | \win32calc.exe | excludes:Image field:"Image" value:"\win32calc.exe" |
Image | is_null | excludes:Image |
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
ParentImage | ends_with |
| field:"ParentImage" kind:ends_with |