Windows Registry: Disable Python function execution warnings in Excel

ATT&CK techniques

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags registry changes to the Excel security setting "PythonFunctionWarnings" under the Microsoft Office Excel path, specifically when the value is set to DWORD 0x00000001. Disabling these warnings can reduce user visibility into Python function execution attempts originating from spreadsheet content, making it easier for malicious workflows to go unnoticed. It relies on telemetry from Windows registry value write events that capture the TargetObject path and the written Details value.

Reporting behind it

Related detections9 linkedT1685 — drag to rearrange

Suspicious Vulnerable Intel Ethernet Driver Load for BYOVD via SCATTERED SPIDER (via driver_load)

Malicious Defender Disable And Executable Exclusion Via Registry

Malicious UAC Disable via EnableLUA Registry Modification (via registry_set)

Malicious AMSI and ETW Patching via PowerShell Script

Malicious PowMix AMSI Bypass via amsiInitFailed

Suspicious ThrottleStop Driver Abuse for Defense Evasion in Ransomware Attacks

Malicious Disabling of Microsoft Defender Real-Time Protection via SystemSettingsAdminFlows by DeadLock Ransomware

Suspicious Security Software Uninstallation via WMIC Product Call Uninstall (Chaos Ransomware)

Suspicious Security Product Uninstall via wmic product call uninstall

Windows Registry: Disable Python function execution warnings in Excel

Pivot detection · T1685 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

windows-registry-disable-python-function-execution-warnings-in-excel-17e53739

title: "Windows Registry: Disable Python function execution warnings in Excel"
id: 2933862c-cec5-4dd3-8bb8-4d4fde1d350c
related:
  - id: 023c654f-8f16-44d9-bb2b-00ff36a62af9
    type: similar
  - id: 17e53739-a1fc-4a62-b1b9-87711c2d5e44
    type: derived
status: test
description: This rule flags registry changes to the Excel security setting "PythonFunctionWarnings" under the Microsoft Office Excel path, specifically when the value is set to DWORD 0x00000001. Disabling these warnings can reduce user visibility into Python function execution attempts originating from spreadsheet content, making it easier for malicious workflows to go unnoticed. It relies on telemetry from Windows registry value write events that capture the TargetObject path and the written Details value.
references:
  - https://support.microsoft.com/en-us/office/data-security-and-python-in-excel-33cc88a4-4a87-485e-9ff9-f35958278327
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/registry/registry_set/registry_set_office_disable_python_security_warnings.yml
author: Nasreddine Bencherchali (Nextron Systems), @Kostastsale, Huntrule Team
date: 2024-08-23
tags:
  - attack.defense-impairment
  - attack.t1685
logsource:
  category: registry_set
  product: windows
detection:
  selection:
    TargetObject|contains: \Microsoft\Office\
    TargetObject|endswith: \Excel\Security\PythonFunctionWarnings
    Details: DWORD (0x00000001)
  condition: selection
falsepositives:
  - Unknown
level: high
license: DRL-1.1

Convert

This rule as a query you can run. Uses no unlock credit.

SplunkSPL