Renamed MegaSync Execution — Sigma Rule

Rule metadata and linked tags

Author: Sittikorn S. Source status: test; severity: high. Source dates: 2021-06-22 / 2023-02-03.

{
  "product": "windows",
  "category": "process_creation"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: d2a3544d1625cbd33812c6bcef2f523cd8600d078fe0c9e72027aae41565e3ea

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Renamed MegaSync Execution
id: 643bdcac-8b82-49f4-9fd9-25a90b929f3b
status: test
description: Detects the execution of a renamed MegaSync.exe as seen used by ransomware families like Nefilim, Sodinokibi, Pysa, and Conti.
references:
    - https://redcanary.com/blog/rclone-mega-extortion/
author: Sittikorn S
date: 2021-06-22
modified: 2023-02-03
tags:
    - attack.stealth
    - attack.t1218
logsource:
    product: windows
    category: process_creation
detection:
    selection:
        OriginalFileName: 'megasync.exe'
    filter:
        Image|endswith: '\megasync.exe'
    condition: selection and not filter
falsepositives:
    - Software that illegally integrates MegaSync in a renamed form
    - Administrators that have renamed MegaSync
level: high

Original YAML and metadata in JSON

False positives

• Software that illegally integrates MegaSync in a renamed form
• Administrators that have renamed MegaSync

Source references

• https://redcanary.com/blog/rclone-mega-extortion/