Windows Network Connection Initiated by finger.exe

Alerts on Windows network connections started by finger.exe, an unusual utility that can support remote command retrieval.

FreeReviewedSigma · High · v2
Product
windows
Category
network_connection
Author
Swachchhanda Shrawan Poudel (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2025-11-19
Updated
2026-07-31
title: Windows Network Connection Initiated by finger.exe
id: de23b6fd-12c7-4b36-8605-d6e64ceb8cbd
related:
  - id: c082c2b0-525b-4dbc-9a26-a57dc4692074
    type: similar
  - id: af491bca-e752-4b44-9c86-df5680533dbc
    type: similar
  - id: 2fdaf50b-9fd5-449f-ba69-f17248119af6
    type: derived
status: experimental
description: This rule flags network connections where the initiating process is finger.exe on Windows. Attackers can abuse the legacy finger protocol to reach out to remote infrastructure for commands or related execution steps. It relies on network connection telemetry that includes process context (specifically the initiating process image ending with \finger.exe).
references:
  - https://www.bleepingcomputer.com/news/security/decades-old-finger-protocol-abused-in-clickfix-malware-attacks/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/network_connection/net_connection_win_finger.yml
author: Swachchhanda Shrawan Poudel (Nextron Systems), Huntrule Team
date: 2025-11-19
tags:
  - attack.command-and-control
  - attack.t1071.004
  - attack.execution
  - attack.t1059.003
logsource:
  category: network_connection
  product: windows
detection:
  selection:
    Initiated: "true"
    Image|endswith: \finger.exe
  condition: selection
falsepositives:
  - Unlikely
level: high
license: DRL-1.1