Suspicious Removal Of SD Value to Hide Schedule Task - Registry (via registry_delete)

title: Suspicious Removal Of SD Value to Hide Schedule Task - Registry (via registry_delete)
id: 813d8a60-0374-56d7-9602-c217f2e73ad5
status: stable
description: This rule detects SD (Security Descriptor) value in \Schedule\TaskCache\Tree registry hive to hide schedule task. This method is used by Tarrask malware
references:
    - https://attack.mitre.org/techniques/T1685/
    - https://www.microsoft.com/security/blog/2022/04/12/tarrask-malware-uses-scheduled-tasks-for-defense-evasion/
author: Huntrule Team
date: 2026-02-21
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    product: windows
    category: registry_delete
detection:
    selection:
        TargetObject|contains|all:
            - '\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Schedule\TaskCache\Tree\'
            - 'SD'
    condition: selection
falsepositives:
    - Unknown
level: medium
regression_tests_path: regression_data/rules/windows/registry/registry_delete/registry_delete_schtasks_hide_task_via_sd_value_removal/info.yml