Uncommon One Time Only Scheduled Task At 00:00 — Sigma Rule

Rule metadata and linked tags

Author: pH-T (Nextron Systems). Source status: test; severity: high. Source dates: 2022-07-15 / 2023-02-03.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: c99629f527a3253db64e6f2e508ae17da0a924f602960ad2bf2279d3301c665c

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: Uncommon One Time Only Scheduled Task At 00:00
id: 970823b7-273b-460a-8afc-3a6811998529
status: test
description: Detects scheduled task creation events that include suspicious actions, and is run once at 00:00
references:
    - https://www.trendmicro.com/vinfo/us/security/news/ransomware-spotlight/ransomware-spotlight-blackbyte
author: pH-T (Nextron Systems)
date: 2022-07-15
modified: 2023-02-03
tags:
    - attack.execution
    - attack.persistence
    - attack.privilege-escalation
    - attack.t1053.005
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|contains: '\schtasks.exe'
        - OriginalFileName: 'schtasks.exe'
    selection_cli:
        CommandLine|contains:
            - 'wscript'
            - 'vbscript'
            - 'cscript'
            - 'wmic '
            - 'wmic.exe'
            - 'regsvr32.exe'
            - 'powershell'
            - '\AppData\'
    selection_time:
        CommandLine|contains|all:
            - 'once'
            - '00:00'
    condition: all of selection_*
falsepositives:
    - Software installation
level: high

Original YAML and metadata in JSON

False positives

• Software installation

Source references

• https://www.trendmicro.com/vinfo/us/security/news/ransomware-spotlight/ransomware-spotlight-blackbyte