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Detection rules › Sigma

Suspicious Rundll32 Activity Invoking Sys File

Status
test
Severity
high
Log source
category process_creation, product windows
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
Stealth

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 1: Process creation
Security-AuditingEvent ID 4688: A new process has been created.

Rule body

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

These rows show field, operator, and value matches.

FieldKindValuesSearch
CommandLinematch
  • .sys
  • .sys,
  • rundll32.exe corpus 8 (sigma 8)
field:"CommandLine" kind:match