Set Suspicious Files as System Files Using Attrib.EXE

Detects the usage of attrib with the "+s" option to set scripts or executables located in suspicious locations as system files to hide them from users and make them unable to be deleted with simple rights. The rule limits the search to specific extensions and directories to avoid FPs

title: Set Suspicious Files as System Files Using Attrib.EXE
id: efec536f-72e8-4656-8960-5e85d091345b
related:
    - id: bb19e94c-59ae-4c15-8c12-c563d23fe52b
      type: derived
status: test
description: |
    Detects the usage of attrib with the "+s" option to set scripts or executables located in suspicious locations as system files to hide them from users and make them unable to be deleted with simple rights. The rule limits the search to specific extensions and directories to avoid FPs
references:
    - https://app.any.run/tasks/c28cabc8-a19f-40f3-a78b-cae506a5c0d4
    - https://app.any.run/tasks/cfc8870b-ccd7-4210-88cf-a8087476a6d0
    - https://unit42.paloaltonetworks.com/unit42-sure-ill-take-new-combojack-malware-alters-clipboards-steal-cryptocurrency/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-06-28
modified: 2023-03-14
tags:
    - attack.stealth
    - attack.t1564.001
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\attrib.exe'
        - OriginalFileName: 'ATTRIB.EXE'
    selection_cli:
        CommandLine|contains: ' +s'
    selection_paths:
        CommandLine|contains:
            - ' %' # Custom Environment variable
            - '\Users\Public\'
            - '\AppData\Local\'
            - '\ProgramData\'
            - '\Downloads\'
            - '\Windows\Temp\'
    selection_ext:
        CommandLine|contains:
            - '.bat'
            - '.dll'
            - '.exe'
            - '.hta'
            - '.ps1'
            - '.vbe'
            - '.vbs'
    filter_optional_installer:
        CommandLine|contains|all:
            - '\Windows\TEMP\'
            - '.exe'
    condition: all of selection* and not 1 of filter_optional_*
falsepositives:
    - Unknown
level: high

• T1564.001Hidden Files and Directories

• https://app.any.run/tasks/c28cabc8-a19f-40f3-a78b-cae506a5c0d4↗
• https://app.any.run/tasks/cfc8870b-ccd7-4210-88cf-a8087476a6d0↗
• https://unit42.paloaltonetworks.com/unit42-sure-ill-take-new-combojack-malware-alters-clipboards-steal-cryptocurrency/↗