HackTool - F-Secure C3 Load by Rundll32 — Sigma Rule

Rule metadata and linked tags

Author: Alfie Champion (ajpc500). Source status: test; severity: critical. Source dates: 2021-06-02 / 2023-03-05.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: ac8341241bbe26f57479b3ecc491d6a17c6f9ad7c87c353f3f453dd3a1c63b65

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: HackTool - F-Secure C3 Load by Rundll32
id: b18c9d4c-fac9-4708-bd06-dd5bfacf200f
status: test
description: F-Secure C3 produces DLLs with a default exported StartNodeRelay function.
references:
    - https://github.com/FSecureLABS/C3/blob/11a081fd3be2aaf2a879f6b6e9a96ecdd24966ef/Src/NodeRelayDll/NodeRelayDll.cpp#L12
author: Alfie Champion (ajpc500)
date: 2021-06-02
modified: 2023-03-05
tags:
    - attack.stealth
    - attack.t1218.011
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains|all:
            - 'rundll32.exe'
            - '.dll'
            - 'StartNodeRelay'
    condition: selection
falsepositives:
    - Unknown
level: critical

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://github.com/FSecureLABS/C3/blob/11a081fd3be2aaf2a879f6b6e9a96ecdd24966ef/Src/NodeRelayDll/NodeRelayDll.cpp#L12