Scheduled Task Deletion

title: Scheduled Task Deletion
id: 4f86b304-3e02-40e3-aa5d-e88a167c9617
status: test
description: Detects scheduled task deletion events. Scheduled tasks are likely to be deleted if not used for persistence. Malicious Software often creates tasks directly under the root node e.g. \TASKNAME
references:
    - https://twitter.com/matthewdunwoody/status/1352356685982146562
    - https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/event-4699
author: David Strassegger, Tim Shelton
date: 2021-01-22
modified: 2023-01-20
tags:
    - attack.execution
    - attack.privilege-escalation
    - attack.persistence
    - car.2013-08-001
    - attack.t1053.005
    - detection.threat-hunting
logsource:
    product: windows
    service: security
    definition: 'Requirements: The Advanced Audit Policy setting Object Access > Audit Other Object Access Events has to be configured to allow this detection. We also recommend extracting the Command field from the embedded XML in the event data.'
detection:
    selection:
        EventID: 4699
    filter_main_generic:
        TaskName: '\Microsoft\Windows\RemovalTools\MRT_ERROR_HB' # Triggered by ParentCommandLine=C:\WINDOWS\system32\MRT.exe /EHB /HeartbeatFailure ErrorStack,Previous=ErrorStack,Previous=ErrorStack,Previous=ErrorStack,Previous=ErrorStack,Previous=SubmitHeartbeatReportData,Hr=0x80072f8f,Hr=0x80072f8f,Hr=0x80072f8f,Hr=0x80072f8f,Hr=0x80072f8f /HeartbeatError 0x80072f8f
    filter_main_firefox:
        TaskName|contains: '\Mozilla\Firefox Default Browser Agent ' # Triggered by firefox updates
    condition: selection and not 1 of filter_*
falsepositives:
    - Software installation
level: low