Unusual Network Connection via RunDLL32

IMPORTANT: This documentation is no longer updated. Refer to Elastic's version policy and the latest documentation.

Unusual Network Connection via RunDLL32

Identifies unusual instances of rundll32.exe making outbound network connections. This may indicate adversarial activity and may identify malicious DLLs.

Rule type: query

Rule indices:

winlogbeat-*

Severity: low

Risk score: 21

Runs every: 5 minutes

Searches indices from: now-6m (Date Math format, see also Additional look-back time)

Maximum signals per execution: 100

Tags:

Elastic
Windows

Version: 2 (version history)

Added (Elastic Stack release): 7.6.0

Last modified (Elastic Stack release): 7.7.0

Rule query

edit

process.name:rundll32.exe and event.action:"Network connection
detected (rule: NetworkConnect)" and not destination.ip:(10.0.0.0/8 or
172.16.0.0/12 or 192.168.0.0/16)

Threat mapping

edit

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Execution
- ID: TA0002
- Reference URL: https://attack.mitre.org/tactics/TA0002/
Technique:
- Name: Rundll32
- ID: T1085
- Reference URL: https://attack.mitre.org/techniques/T1085/

Rule version history

edit

Version 2 (7.7.0 release)

Updated query, changed from:

process.name:rundll32.exe and event.action:"Network connection
detected (rule: NetworkConnect)" and not destination.ip:10.0.0.0/8 and
not destination.ip:172.16.0.0/12 and not destination.ip:192.168.0.0/16

« Unusual Login Activity Unusual Network Destination Domain Name »