Suspicious Schtasks Execution AppData Folder

SIGMA detection rule by pH-T (Nextron Systems), Nasreddine Bencherchali (Nextron Systems) · NOASSERTION

Detects the creation of a schtask that executes a file from C:\Users\<USER>\AppData\Local

title: Suspicious Schtasks Execution AppData Folder
id: c5c00f49-b3f9-45a6-997e-cfdecc6e1967
status: test
description: 'Detects the creation of a schtask that executes a file from C:\Users\<USER>\AppData\Local'
references:
    - https://thedfirreport.com/2022/02/21/qbot-and-zerologon-lead-to-full-domain-compromise/
author: pH-T (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)
date: 2022-03-15
modified: 2022-07-28
tags:
    - attack.privilege-escalation
    - attack.execution
    - attack.persistence
    - attack.t1053.005
    - attack.t1059.001
logsource:
    product: windows
    category: process_creation
detection:
    selection:
        Image|endswith: '\schtasks.exe'
        CommandLine|contains|all:
            - '/Create'
            - '/RU'
            - '/TR'
            - 'C:\Users\'
            - '\AppData\Local\'
        CommandLine|contains:
            - 'NT AUT' # This covers the usual NT AUTHORITY\SYSTEM
            - ' SYSTEM ' # SYSTEM is a valid value for schtasks hence it gets it's own value with space
    filter:
        # FP from test set in SIGMA
        ParentImage|contains|all:
            - '\AppData\Local\Temp\'
            - 'TeamViewer_.exe'
        Image|endswith: '\schtasks.exe'
        CommandLine|contains: '/TN TVInstallRestore'
    condition: selection and not filter
falsepositives:
    - Unknown
level: high

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

3849a547-9550-4cd1-9778-dc60fdc92316

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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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