Unusual Child Processes of RunDLL32

Last updated 12 days ago on 2026-04-30
Created 6 years ago on 2020-09-02

About

Identifies a no-argument or malformed Rundll32 launch followed by child process execution. This unusual sequence can indicate Rundll32 abuse for proxy execution or payload handoff.
Tags
Domain: EndpointOS: WindowsUse Case: Threat DetectionTactic: Defense EvasionData Source: Elastic DefendData Source: SysmonData Source: CrowdstrikeLanguage: eql
Severity
high
Risk Score
73
MITRE ATT&CK™

Defense Evasion (TA0005)(external, opens in a new tab or window)

License
Elastic License v2(external, opens in a new tab or window)

Definition

Rule Type
Event Correlation Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
logs-endpoint.events.process-*winlogbeat-*logs-windows.sysmon_operational-*logs-crowdstrike.fdr*
Related Integrations

endpoint(external, opens in a new tab or window)

windows(external, opens in a new tab or window)

crowdstrike(external, opens in a new tab or window)

Query
text code block:
sequence with maxspan=1h [process where host.os.type == "windows" and event.type == "start" and (process.name : "rundll32.exe" or process.pe.original_file_name == "RUNDLL32.EXE") and (process.args_count == 1 and /* Excludes bug where a missing closing quote sets args_count to 1 despite extra args */ not process.command_line regex~ """\".*\.exe[^\"].*""") ] by process.entity_id [process where host.os.type == "windows" and event.type == "start" and process.parent.name : "rundll32.exe" ] by process.parent.entity_id

Install detection rules in Elastic Security

Detect Unusual Child Processes of RunDLL32 in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(external, opens in a new tab or window).