Windows: Process creation of UltraVNC VNCViewer (VNCViewer.exe)

Flags execution of UltraVNC VNCViewer.exe on Windows based on process creation metadata.

FreeUnreviewedSigmamediumv1

windows-process-creation-of-ultravnc-vncviewer-vncviewer-exe-145322e4

title: "Windows: Process creation of UltraVNC VNCViewer (VNCViewer.exe)"
id: ad71f3b3-4922-4868-a998-a7c2e8c8f2e2
status: test
description: This rule identifies the execution of UltraVNC’s VNCViewer component by matching process creation fields for VNCViewer.exe with product, company, and original filename metadata. Attackers can use legitimate remote access tooling to establish interactive control over systems inside a network. It relies on Windows process creation telemetry and executable metadata such as Product, Company, Description, and OriginalFileName.
references:
  - https://github.com/redcanaryco/atomic-red-team/blob/9e5b12c4912c07562aec7500447b11fa3e17e254/atomics/T1219/T1219.md
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_ultravnc.yml
author: frack113, Huntrule Team
date: 2022-10-02
tags:
  - attack.command-and-control
  - attack.t1219.002
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    - Description: VNCViewer
    - Product: UltraVNC VNCViewer
    - Company: UltraVNC
    - OriginalFileName: VNCViewer.exe
  condition: selection
falsepositives:
  - Legitimate use
level: medium
license: DRL-1.1
related:
  - id: 145322e4-0fd3-486b-81ca-9addc75736d8
    type: derived

What it detects

This rule identifies the execution of UltraVNC’s VNCViewer component by matching process creation fields for VNCViewer.exe with product, company, and original filename metadata. Attackers can use legitimate remote access tooling to establish interactive control over systems inside a network. It relies on Windows process creation telemetry and executable metadata such as Product, Company, Description, and OriginalFileName.

Known false positives

Legitimate use

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.