Obfuscated PowerShell MSI Install via WindowsInstaller COM
Detects the execution of obfuscated PowerShell commands that attempt to install MSI packages via the Windows Installer COM object (`WindowsInstaller.Installer`). The technique involves manipulating strings to hide…
Description
Detects the execution of obfuscated PowerShell commands that attempt to install MSI packages via the Windows Installer COM object (`WindowsInstaller.Installer`). The technique involves manipulating strings to hide functionality, such as constructing class names using string insertion (e.g., 'indowsInstaller.Installer'.Insert(0,'W')) and correcting malformed URLs (e.g., converting 'htps://' to 'https://') at runtime. This behavior is commonly associated with malware loaders or droppers that aim to bypass static detection by hiding intent in runtime-generated strings and using legitimate tools for code execution. The use of `InstallProduct` and COM object creation, particularly combined with hidden window execution and suppressed UI, indicates an attempt to install software (likely malicious) without user interaction.
Detection logic
Detection requirements
- Platform
- LinuxmacOSWindows
The rule states no platform. This is derived from the 3 ATT&CK techniques it maps to.
- Log source product
- windows
- Log source category
- process_creation
Known benign triggers
- Unknown
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| informationsecuritybuzz.com/the-real-danger-behind-a-simple-windows-shortcut/ | 2 |
| redcanary.com/blog/threat-intelligence/intelligence-insights-may-2025/ | 2 |
| www.virustotal.com/gui/file/f9710b0ba4de5fa0e7ec27da462d4d2fc6838eba83a19f23f6617a466bbad457 | 2 |
From the source
- At source
- Open at source
- Upstream identifier
- 7b6a7418-3afc-11f0-aff4-000d3abf478c
- Tagged by the source as
- attack.executionattack.stealth
Licence
- Published under
- Detection Rule License 1.1Read the licence
- Attribution
- Required
Authorship
- Written by
- Published
- Aug 26, 2026
- Version
- 1