Sigma rule: Suspicious Rundll32 Activity Invoking Sys File

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-2e2bdafef2e7, updated 2022-10-09T00:00:00.000Z.

Rule

Title
Suspicious Rundll32 Activity Invoking Sys File
Status
test
Level
high
Author
Florian Roth (Nextron Systems)
Date
2021-03-05
Modified
2022-10-09
File
rules/windows/process_creation/proc_creation_win_rundll32_sys.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects suspicious process related to rundll32 based on command line that includes a *.sys file as seen being used by UNC2452

Log source

product
windows
category
process_creation

Detection

selection1:
    CommandLine|contains: 'rundll32.exe'
selection2:
    CommandLine|contains:
        - '.sys,'
        - '.sys '
condition: all of selection*

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.stealth
  • attack.t1218.011

MITRE ATT&CK ids this rule names

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_rundll32_sys.yml

Sources and licences

  • SigmaHQ

    "Suspicious Rundll32 Activity Invoking Sys File" by Florian Roth (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_rundll32_sys.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Suspicious Rundll32 Activity Invoking Sys File",
entity page, dataset version ref-2e2bdafef2e7, updated 2022-10-09T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/731231b9-0b5d-4219-94dd-abb6959aa7ea (accessed 2026-11-03).
Underlying source: SigmaHQ rule 731231b9-0b5d-4219-94dd-abb6959aa7ea, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.