Potentially Suspicious Event Viewer Child Process

Severity: high
Author: Florian Roth (Nextron Systems)
Source: upstream

Detects uncommon or suspicious child processes of "eventvwr.exe" which might indicate a UAC bypass attempt

MITRE ATT&CK coverage

Tactic	Techniques
Privilege Escalation	`T1548.002` Abuse Elevation Control Mechanism: Bypass User Account Control
Defense Evasion	`T1548.002` Abuse Elevation Control Mechanism: Bypass User Account Control

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation
Security-Auditing	4688	A new process has been created.

Stages and Predicates

Stage 1: `selection`

ParentImage|endswith: '\eventvwr.exe'

Stage 2: `not 1 of filter_main_generic`

or:
Image|endswith: ':\Windows\SysWOW64\WerFault.exe'
Image|endswith: ':\Windows\System32\WerFault.exe'
Image|endswith: ':\Windows\System32\mmc.exe'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`Image`	ends_with	`:\Windows\SysWOW64\WerFault.exe` `:\Windows\System32\WerFault.exe` `:\Windows\System32\mmc.exe` corpus 3 (sigma 3)
`ParentImage`	ends_with	`\eventvwr.exe` corpus 2 (sigma 2)