title: Path To Screensaver Binary Modified
id: 67a6c006-3fbe-46a7-9074-2ba3b82c3000
status: test
description: Detects value modification of registry key containing path to binary used as screensaver.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1546.002/T1546.002.md
    - https://www.welivesecurity.com/wp-content/uploads/2017/08/eset-gazer.pdf
author: Bartlomiej Czyz @bczyz1, oscd.community
date: 2020-10-11
modified: 2021-11-27
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.t1546.002
logsource:
    category: registry_event
    product: windows
detection:
    selection:
        TargetObject|endswith: '\Control Panel\Desktop\SCRNSAVE.EXE' # HKEY_CURRENT_USER\Control Panel\Desktop\SCRNSAVE.EXE
    filter:
        Image|endswith:
            - '\rundll32.exe'
            - '\explorer.exe'
    condition: selection and not filter
falsepositives:
    - Legitimate modification of screensaver
level: medium

title: Suspicious ScreenSave Change by Reg.exe
id: 0fc35fc3-efe6-4898-8a37-0b233339524f
status: test
description: |
    Adversaries may establish persistence by executing malicious content triggered by user inactivity.
    Screensavers are programs that execute after a configurable time of user inactivity and consist of Portable Executable (PE) files with a .scr file extension
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1546.002/T1546.002.md
    - https://www.welivesecurity.com/wp-content/uploads/2017/08/eset-gazer.pdf
author: frack113
date: 2021-08-19
modified: 2022-06-02
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.t1546.002
logsource:
    category: process_creation
    product: windows
detection:
    selection_reg:
        Image|endswith: '\reg.exe'
        CommandLine|contains:
            - 'HKEY_CURRENT_USER\Control Panel\Desktop'
            - 'HKCU\Control Panel\Desktop'
    selection_option_1: # /force Active ScreenSaveActive
        CommandLine|contains|all:
            - '/v ScreenSaveActive'
            - '/t REG_SZ'
            - '/d 1'
            - '/f'
    selection_option_2: # /force  set ScreenSaveTimeout
        CommandLine|contains|all:
            - '/v ScreenSaveTimeout'
            - '/t REG_SZ'
            - '/d '
            - '/f'
    selection_option_3: # /force set ScreenSaverIsSecure
        CommandLine|contains|all:
            - '/v ScreenSaverIsSecure'
            - '/t REG_SZ'
            - '/d 0'
            - '/f'
    selection_option_4: # /force set a .scr
        CommandLine|contains|all:
            - '/v SCRNSAVE.EXE'
            - '/t REG_SZ'
            - '/d '
            - '.scr'
            - '/f'
    condition: selection_reg and 1 of selection_option_*
falsepositives:
    - GPO
level: medium

title: Suspicious Screensaver Binary File Creation
id: 97aa2e88-555c-450d-85a6-229bcd87efb8
status: test
description: |
    Adversaries may establish persistence by executing malicious content triggered by user inactivity.
    Screensavers are programs that execute after a configurable time of user inactivity and consist of Portable Executable (PE) files with a .scr file extension
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1546.002/T1546.002.md
author: frack113
date: 2021-12-29
modified: 2022-11-08
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1546.002
logsource:
    product: windows
    category: file_event
detection:
    selection:
        TargetFilename|endswith: '.scr'
    filter_generic:
        Image|endswith:
            - '\Kindle.exe'
            - '\Bin\ccSvcHst.exe' # Symantec Endpoint Protection
    filter_tiworker:
        # ParentCommandLine: C:\WINDOWS\system32\svchost.exe -k DcomLaunch -p
        Image|endswith: '\TiWorker.exe'
        TargetFilename|endswith: '\uwfservicingscr.scr'
    condition: selection and not 1 of filter_*
falsepositives:
    - Unknown
level: medium

title: Writing Local Admin Share
id: 4aafb0fa-bff5-4b9d-b99e-8093e659c65f
status: test
description: |
    Aversaries may use to interact with a remote network share using Server Message Block (SMB).
    This technique is used by post-exploitation frameworks.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1021.002/T1021.002.md#atomic-test-4---execute-command-writing-output-to-local-admin-share
author: frack113
date: 2022-01-01
modified: 2022-08-13
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.lateral-movement
    - attack.t1546.002
logsource:
    product: windows
    category: file_event
detection:
    selection:
        TargetFilename|contains|all:
            - '\\\\127.0.0'
            - '\ADMIN$\'
    condition: selection
falsepositives:
    - Unknown
level: medium