HackTool - F-Secure C3 Load by Rundll32

Status: test
Severity: critical
Log source: category process_creation, product windows
Author: Alfie Champion (ajpc500)
Source: github.com/SigmaHQ/sigma

F-Secure C3 produces DLLs with a default exported StartNodeRelay function.

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	`T1218.011` System Binary Proxy Execution: Rundll32

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation
Security-Auditing	Event ID 4688: A new process has been created.

Rule body

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

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    CommandLine|contains|all:
        - 'rundll32.exe'
        - '.dll'
        - 'StartNodeRelay'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`.dll` corpus 16 (sigma 16) `StartNodeRelay` `rundll32.exe` corpus 8 (sigma 8)	`field:"CommandLine" kind:match`

HackTool - F-Secure C3 Load by Rundll32

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection

Indicators

Stage 0: `condition`

Stage 1: `selection`