Potential Signing Bypass Via Windows Developer Features - Registry

Hunt Hypothesis

Detects when the enablement of developer features such as “Developer Mode” or “Application Sideloading”. Which allows the user to install untrusted packages.

Detection Rule

Sigma (Original)

title: Potential Signing Bypass Via Windows Developer Features - Registry
id: b110ebaf-697f-4da1-afd5-b536fa27a2c1
related:
    - id: a383dec4-deec-4e6e-913b-ed9249670848
      type: similar
status: test
description: Detects when the enablement of developer features such as "Developer Mode" or "Application Sideloading". Which allows the user to install untrusted packages.
references:
    - https://twitter.com/malmoeb/status/1560536653709598721
    - https://www.sentinelone.com/labs/inside-malicious-windows-apps-for-malware-deployment/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-01-12
modified: 2023-08-17
tags:
    - attack.stealth
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|contains:
            - '\Microsoft\Windows\CurrentVersion\AppModelUnlock'
            - '\Policies\Microsoft\Windows\Appx\'
        TargetObject|endswith:
            - '\AllowAllTrustedApps'
            - '\AllowDevelopmentWithoutDevLicense'
        Details: 'DWORD (0x00000001)'
    condition: selection
falsepositives:
    - Unknown
level: high

KQL (Azure Sentinel)

imRegistry
| where (RegistryKey contains "\\Microsoft\\Windows\\CurrentVersion\\AppModelUnlock" or RegistryKey endswith "\\Policies\\Microsoft\\Windows\\Appx*") and (RegistryKey endswith "\\AllowAllTrustedApps" or RegistryKey endswith "\\AllowDevelopmentWithoutDevLicense") and RegistryValueData =~ "DWORD (0x00000001)"

KQL (Microsoft 365 Defender)

DeviceRegistryEvents
| where (RegistryKey contains "\\Microsoft\\Windows\\CurrentVersion\\AppModelUnlock" or RegistryKey endswith "\\Policies\\Microsoft\\Windows\\Appx*") and (RegistryKey endswith "\\AllowAllTrustedApps" or RegistryKey endswith "\\AllowDevelopmentWithoutDevLicense") and RegistryValueData =~ "DWORD (0x00000001)"

Required Data Sources

False Positive Guidance

• Unknown

References

• https://twitter.com/malmoeb/status/1560536653709598721
• https://www.sentinelone.com/labs/inside-malicious-windows-apps-for-malware-deployment/
• SigmaHQ Rule