Python Image Load By Non-Python Process

Hunt Hypothesis

Detects the image load of “Python Core” by a non-Python process. This might be indicative of a execution of executable that has been bundled from Python code. Various tools like Py2Exe, PyInstaller, a

Detection Rule

Sigma (Original)

title: Python Image Load By Non-Python Process
id: cbb56d62-4060-40f7-9466-d8aaf3123f83
status: test
description: |
    Detects the image load of "Python Core" by a non-Python process. This might be indicative of a execution of executable that has been bundled from Python code.
    Various tools like Py2Exe, PyInstaller, and cx_Freeze are used to bundle Python code into standalone executables.
    Threat actors often use these tools to bundle malicious Python scripts into executables, sometimes to obfuscate the code or to bypass security measures.
references:
    - https://www.py2exe.org/
    - https://unit42.paloaltonetworks.com/unit-42-technical-analysis-seaduke/
author: Patrick St. John, OTR (Open Threat Research)
date: 2020-05-03
modified: 2025-08-18
tags:
    - attack.stealth
    - attack.t1027.002
logsource:
    product: windows
    category: image_load
detection:
    selection:
        Description: 'Python Core'
    filter_main_generic:
        - Image|contains: 'Python'  # FPs with python38.dll, python.exe etc.
        - Image|startswith:
              - 'C:\Program Files\'
              - 'C:\Program Files (x86)\'
              - 'C:\ProgramData\Anaconda3\' # Comment out if you don't use Anaconda in your environment
    filter_optional_null_image:
        Image: null
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Legitimate Py2Exe Binaries
    - Known false positive caused with Python Anaconda
    - Various legitimate software is bundled from Python code into executables
level: low

KQL (Microsoft 365 Defender)

DeviceImageLoadEvents
| where InitiatingProcessVersionInfoFileDescription =~ "Python Core" and (not((InitiatingProcessFolderPath contains "Python" or (InitiatingProcessFolderPath startswith "C:\\Program Files\\" or InitiatingProcessFolderPath startswith "C:\\Program Files (x86)\\" or InitiatingProcessFolderPath startswith "C:\\ProgramData\\Anaconda3\\")))) and (not(isnull(InitiatingProcessFolderPath)))

Required Data Sources

False Positive Guidance

• Legitimate Py2Exe Binaries
• Known false positive caused with Python Anaconda
• Various legitimate software is bundled from Python code into executables

MITRE ATT&CK Context

• Technique: T1027.002 — T1027.002

References

• https://www.py2exe.org/
• https://unit42.paloaltonetworks.com/unit-42-technical-analysis-seaduke/
• SigmaHQ Rule