Suspicious Rundll32 Activity Invoking Sys File — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems). Source status: test; severity: high. Source dates: 2021-03-05 / 2022-10-09.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: c04a0e54cce5f0c435841ab7ef1e349d3a3aa6e76189ad3bef58bf2c3018572b

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Suspicious Rundll32 Activity Invoking Sys File
id: 731231b9-0b5d-4219-94dd-abb6959aa7ea
status: test
description: Detects suspicious process related to rundll32 based on command line that includes a *.sys file as seen being used by UNC2452
references:
    - https://www.microsoft.com/security/blog/2021/03/04/goldmax-goldfinder-sibot-analyzing-nobelium-malware/
author: Florian Roth (Nextron Systems)
date: 2021-03-05
modified: 2022-10-09
tags:
    - attack.stealth
    - attack.t1218.011
logsource:
    category: process_creation
    product: windows
detection:
    selection1:
        CommandLine|contains: 'rundll32.exe'
    selection2:
        CommandLine|contains:
            - '.sys,'
            - '.sys '
    condition: all of selection*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.microsoft.com/security/blog/2021/03/04/goldmax-goldfinder-sibot-analyzing-nobelium-malware/