Suspicious Scheduled Task Creation via Masqueraded XML File

SIGMA detection rule by Swachchhanda Shrawan Poudel, Elastic (idea) · NOASSERTION

Detects the creation of a scheduled task using the "-XML" flag with a file without the '.xml' extension. This behavior could be indicative of potential defense evasion attempt during persistence

title: Suspicious Scheduled Task Creation via Masqueraded XML File
id: dd2a821e-3b07-4d3b-a9ac-929fe4c6ca0c
status: test
description: Detects the creation of a scheduled task using the "-XML" flag with a file without the '.xml' extension. This behavior could be indicative of potential defense evasion attempt during persistence
references:
    - https://learn.microsoft.com/en-us/windows/win32/taskschd/daily-trigger-example--xml-
    - https://github.com/elastic/protections-artifacts/blob/084067123d3328a823b1c3fdde305b694275c794/behavior/rules/persistence_suspicious_scheduled_task_creation_via_masqueraded_xml_file.toml
author: Swachchhanda Shrawan Poudel, Elastic (idea)
date: 2023-04-20
modified: 2024-12-01
tags:
    - attack.privilege-escalation
    - attack.execution
    - attack.persistence
    - attack.stealth
    - attack.t1036.005
    - attack.t1053.005
logsource:
    product: windows
    category: process_creation
detection:
    selection_img:
        - Image|endswith: '\schtasks.exe'
        - OriginalFileName: 'schtasks.exe'
    selection_cli_create:
        CommandLine|contains:
            - '/create'
            - '-create'
    selection_cli_xml:
        CommandLine|contains:
            - '/xml'
            - '-xml'
    filter_main_extension_xml:
        CommandLine|contains: '.xml'
    filter_main_system_process:
        IntegrityLevel:
            - 'System'
            - 'S-1-16-16384'
    filter_main_rundll32:
        ParentImage|endswith: '\rundll32.exe'
        ParentCommandLine|contains|all:
            - ':\WINDOWS\Installer\MSI'
            - '.tmp,zzzzInvokeManagedCustomActionOutOfProc'
    filter_optional_third_party:
        ParentImage|endswith:
            # Consider removing any tools that you don't use to avoid blind spots
            - ':\ProgramData\OEM\UpgradeTool\CareCenter_*\BUnzip\Setup_msi.exe'
            - ':\Program Files\Axis Communications\AXIS Camera Station\SetupActions.exe'
            - ':\Program Files\Axis Communications\AXIS Device Manager\AdmSetupActions.exe'
            - ':\Program Files (x86)\Zemana\AntiMalware\AntiMalware.exe'
            - ':\Program Files\Dell\SupportAssist\pcdrcui.exe'
    condition: all of selection_* and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Unknown
level: medium

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

6850855a-b14f-47bb-a6ba-850d427730a3

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

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Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

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[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

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