SigmaHQ/rules/windows/process_creation/win_susp_userinit_child.yml

title: Suspicious Userinit Child Process
id: b655a06a-31c0-477a-95c2-3726b83d649d
status: experimental
description: Detects a suspicious child process of userinit
references:
    - https://twitter.com/SBousseaden/status/1139811587760562176
author: Florian Roth (rule), Samir Bousseaden (idea)
date: 2019/06/17
modified: 2021/06/27
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\userinit.exe'
    filter1:
        CommandLine|contains: '\netlogon\'
    filter2:
        Image|endswith: '\explorer.exe'
    condition: selection and not filter1 and not filter2
fields:
    - CommandLine
    - ParentCommandLine
falsepositives:
    - Administrative scripts
level: medium
Rule: Suspicious userinit.exe child process 2019-06-23 11:27:06 +00:00			`title: Suspicious Userinit Child Process`
Added UUIDs to rules 2019-11-12 22:12:27 +00:00			`id: b655a06a-31c0-477a-95c2-3726b83d649d`
Rule: Suspicious userinit.exe child process 2019-06-23 11:27:06 +00:00			`status: experimental`
fix: more FP reductions 2019-11-09 22:36:29 +00:00			`description: Detects a suspicious child process of userinit`
Added UUIDs to rules 2019-11-12 22:12:27 +00:00			`references:`
Rule: Suspicious userinit.exe child process 2019-06-23 11:27:06 +00:00			`- https://twitter.com/SBousseaden/status/1139811587760562176`
			`author: Florian Roth (rule), Samir Bousseaden (idea)`
			`date: 2019/06/17`
Added missing "modified" fields. Removed trailing wildcard. 2021-06-27 15:36:32 +00:00			`modified: 2021/06/27`
Rule: Suspicious userinit.exe child process 2019-06-23 11:27:06 +00:00			`logsource:`
			`category: process_creation`
			`product: windows`
			`detection:`
			`selection:`
Update win_susp_userinit_child.yml 2020-10-15 22:51:42 +00:00			`ParentImage\|endswith: '\userinit.exe'`
fix: more FP reductions 2019-11-09 22:36:29 +00:00			`filter1:`
Updated rules with modifiers instead of '*' and remove trailing '\\' 2021-06-27 12:51:29 +00:00			`CommandLine\|contains: '\netlogon\'`
fix: more FP reductions 2019-11-09 22:36:29 +00:00			`filter2:`
Update win_susp_userinit_child.yml 2020-10-15 22:51:42 +00:00			`Image\|endswith: '\explorer.exe'`
fix: more FP reductions 2019-11-09 22:36:29 +00:00			`condition: selection and not filter1 and not filter2`
Rule: Suspicious userinit.exe child process 2019-06-23 11:27:06 +00:00			`fields:`
			`- CommandLine`
			`- ParentCommandLine`
			`falsepositives:`
			`- Administrative scripts`
fix: more FP reductions 2019-11-09 22:36:29 +00:00			`level: medium`