Detection rules › Sigma

FunkLocker Ransomware File Creation

Status
experimental
Severity
high
Log source
category file_event, product windows
Author
Saiprashanth Pulisetti ( @Prashanthblogs)
Source
github.com/SigmaHQ/sigma

Detects the creation of files with the ".funksec" extension, which is appended to encrypted files by the FunkLocker ransomware.

Known false positives

  • Unlikely

MITRE ATT&CK coverage

TacticTechniques
Impact

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 11: FileCreate

Rule body

title: FunkLocker Ransomware File Creation
id: 2c76a22b-702d-48fd-8fa9-e41e2fe203b3
status: experimental
description: Detects the creation of files with the ".funksec" extension, which is appended to encrypted files by the FunkLocker ransomware.
references:
    - https://www.broadcom.com/support/security-center/protection-bulletin/funksec-ransomware
    - https://www.pcrisk.com/removal-guides/31853-funklocker-funksec-ransomware
author: Saiprashanth Pulisetti ( @Prashanthblogs)
date: 2025-08-08
tags:
    - attack.impact
    - attack.t1486
    - detection.emerging-threats
logsource:
    category: file_event
    product: windows
detection:
    selection:
        TargetFilename|endswith: '.funksec'
    condition: selection
falsepositives:
    - Unlikely
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    TargetFilename|endswith: '.funksec'

Indicators

These rows show field, operator, and value matches.