detection.wiki

Detection rules › Sigma

Suspicious Rundll32 Activity Invoking Sys File

Status
test
Severity
high
Log source
product windows, category process_creation
Author
Florian Roth (Nextron Systems)
Source
github.com/SigmaHQ/sigma

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

MITRE ATT&CK coverage

TacticTechniques
StealthT1218.011 System Binary Proxy Execution: Rundll32

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation
Security-AuditingEvent ID 4688A new process has been created.

Rule body yaml

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

Stages and Predicates

Stage 0: condition

all of selection*

Stage 1: selection1

selection1:
    CommandLine|contains: 'rundll32.exe'

Stage 2: selection2

selection2:
    CommandLine|contains:
        - '.sys,'
        - '.sys '

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
CommandLinematch
  • .sys
  • .sys,
  • rundll32.exe corpus 8 (sigma 8)