Tasks Folder Evasion

Hunt Hypothesis

The Tasks folder in system32 and syswow64 are globally writable paths. Adversaries can take advantage of this and load or influence any script hosts or ANY .NET Application in Tasks to load and execut

Detection Rule

Sigma (Original)

title: Tasks Folder Evasion
id: cc4e02ba-9c06-48e2-b09e-2500cace9ae0
status: test
description: |
    The Tasks folder in system32 and syswow64 are globally writable paths.
    Adversaries can take advantage of this and load or influence any script hosts or ANY .NET Application
    in Tasks to load and execute a custom assembly into cscript, wscript, regsvr32, mshta, eventvwr
references:
    - https://twitter.com/subTee/status/1216465628946563073
    - https://gist.github.com/am0nsec/8378da08f848424e4ab0cc5b317fdd26
author: Sreeman
date: 2020-01-13
modified: 2022-12-25
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.execution
    - attack.stealth
    - attack.t1574.001
logsource:
    product: windows
    category: process_creation
detection:
    selection1:
        CommandLine|contains:
            - 'echo '
            - 'copy '
            - 'type '
            - 'file createnew'
    selection2:
        CommandLine|contains:
            - ' C:\Windows\System32\Tasks\'
            - ' C:\Windows\SysWow64\Tasks\'
    condition: all of selection*
falsepositives:
    - Unknown
level: high

KQL (Azure Sentinel)

imProcessCreate
| where (TargetProcessCommandLine contains "echo " or TargetProcessCommandLine contains "copy " or TargetProcessCommandLine contains "type " or TargetProcessCommandLine contains "file createnew") and (TargetProcessCommandLine contains " C:\\Windows\\System32\\Tasks\\" or TargetProcessCommandLine contains " C:\\Windows\\SysWow64\\Tasks\\")

Required Data Sources

False Positive Guidance

• Unknown

MITRE ATT&CK Context

• Tactic: Privilege Escalation
• Tactic: Persistence
• Tactic: Execution
• Technique: T1574.001 — T1574.001

References

• https://twitter.com/subTee/status/1216465628946563073
• https://gist.github.com/am0nsec/8378da08f848424e4ab0cc5b317fdd26
• SigmaHQ Rule