title: Python One-Liners with Base64 Decoding
id: 50a0aa3d-ab16-4594-a8aa-5145a6e6792b
related:
    - id: 55e862a8-dd9c-4651-807a-f21fcad56716
      type: similar
status: experimental
description: |
    Detects Python one-liners that use base64 decoding functions in command line executions.
    Malicious scripts or attackers often use python one-liners to decode and execute base64-encoded payloads, which is a common technique for obfuscation and evasion.
references:
    - https://docs.python.org/3/library/base64.html
    - https://www.virustotal.com/gui/file/bc43e925d7b4b74319f6e74e836a96f1997ba404e14ac566cf12a21e9da463db/behavior
    - https://cloud.google.com/blog/topics/threat-intelligence/cybercriminals-weaponize-fake-ai-websites
author: Hugh Ryan (HueCodes), Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2026-03-09
tags:
    - attack.execution
    - attack.stealth
    - attack.t1059.006
    - attack.t1027.010
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|contains: '\python'
        - OriginalFileName|contains: 'python'
    selection_cli:
        CommandLine|contains|all:
            - 'import'
            - 'base64'
            - ' -c'
        CommandLine|contains:
            - '.decode'
            - 'b16decode'
            - 'b32decode'
            - 'b32hexdecode'
            - 'b64decode'
            - 'b85decode'
            - 'z85decode'
    condition: all of selection_*
falsepositives:
    - Legitimate use of Python for decoding data, which is uncommon in typical enterprise environments but possible in development or data analysis contexts.
level: high
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_python_base64_encoded_execution/info.yml

title: Python One-Liners with Base64 Decoding - Linux
id: 55e862a8-dd9c-4651-807a-f21fcad56716
related:
    - id: 50a0aa3d-ab16-4594-a8aa-5145a6e6792b
      type: similar
status: experimental
description: |
    Detects the use of Python's base64 decoding functions in command line executions on Linux systems.
    Malicious scripts often use python one-liners to decode and execute base64-encoded payloads, which is a common technique for obfuscation and evasion.
references:
    - https://docs.python.org/3/library/base64.html
    - https://www.virustotal.com/gui/file/bc43e925d7b4b74319f6e74e836a96f1997ba404e14ac566cf12a21e9da463db/behavior
    - https://cloud.google.com/blog/topics/threat-intelligence/cybercriminals-weaponize-fake-ai-websites
author: Hugh Ryan (HueCodes), Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2026-03-09
tags:
    - attack.execution
    - attack.stealth
    - attack.t1059.006
    - attack.t1027.010
logsource:
    category: process_creation
    product: linux
detection:
    selection_img:
        Image|contains: '/python'
    selection_cli:
        CommandLine|contains|all:
            - 'import'
            - 'base64'
            - ' -c'
        CommandLine|contains:
            - '.decode'
            - 'b16decode'
            - 'b32decode'
            - 'b32hexdecode'
            - 'b64decode'
            - 'b85decode'
            - 'z85decode'
    condition: all of selection_*
falsepositives:
    - Legitimate use of Python for decoding data, which is uncommon in typical enterprise environments but possible in development or data analysis contexts.
level: high

title: AppLocker Prevented Application or Script from Running
id: 401e5d00-b944-11ea-8f9a-00163ecd60ae
status: test
description: |
    Detects when AppLocker prevents the execution of an Application, DLL, Script, MSI, or Packaged-App from running.
references:
    - https://learn.microsoft.com/en-us/windows/security/application-security/application-control/windows-defender-application-control/applocker/what-is-applocker
    - https://learn.microsoft.com/en-us/windows/security/application-security/application-control/windows-defender-application-control/applocker/using-event-viewer-with-applocker
    - https://nxlog.co/documentation/nxlog-user-guide/applocker.html
author: Pushkarev Dmitry
date: 2020-06-28
modified: 2025-12-03
tags:
    - attack.execution
    - attack.t1204.002
    - attack.t1059.001
    - attack.t1059.003
    - attack.t1059.005
    - attack.t1059.006
    - attack.t1059.007
logsource:
    product: windows
    service: applocker
detection:
    selection:
        EventID:
            - 8004 # EXE and DLL
            - 8007 # MSI and Script
            - 8022 # Packaged app execution
            - 8025 # Packaged app deployment
    condition: selection
falsepositives:
    - Unlikely, since this event notifies about blocked application execution. Tune your applocker rules to avoid blocking legitimate applications.
level: medium

title: Suspicious File Characteristics Due to Missing Fields
id: 9637e8a5-7131-4f7f-bdc7-2b05d8670c43
status: test
description: Detects Executables in the Downloads folder without FileVersion,Description,Product,Company likely created with py2exe
references:
    - https://securelist.com/muddywater/88059/
    - https://www.virustotal.com/#/file/276a765a10f98cda1a38d3a31e7483585ca3722ecad19d784441293acf1b7beb/detection
author: Markus Neis, Sander Wiebing
date: 2018-11-22
modified: 2022-10-09
tags:
    - attack.execution
    - attack.t1059.006
logsource:
    product: windows
    category: process_creation
detection:
    selection1:
        Description: '\?'
        FileVersion: '\?'
    selection2:
        Description: '\?'
        Product: '\?'
    selection3:
        Description: '\?'
        Company: '\?'
    folder:
        Image|contains: '\Downloads\'
    condition: (selection1 or selection2 or selection3) and folder
falsepositives:
    - Unknown
level: medium