Query: write Sigma for Detects the execution of obfuscated PowerShell commands that attempt to install MSI packages via the Windows Installer C
Matching passage: Sigma rule: Detects the execution of obfuscated PowerShell commands that attempt to install MSI packages via the Windows Installer C. Logsource: windows / process_creation. Rule: title: Obfuscated PowerShell MSI Install via WindowsInstaller COM id: 7b6a7418-3afc-11f0-aff4-000d3abf478c status: experimental 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. ' references: - https://informationsecuritybuzz.com/the-real-danger-behind-a-simple-windows-shortcut/ - https://redcanary.com/blog/threat-intelligence/intelligence-insights-may-2025/ - https://www.virustotal.com/gui/file/f9710b0ba4de5fa0e7ec27da462d4d2fc6838eba83a19f23f6617a466bbad457 author: Meroujan Antonyan (vx3r) date: 2025-05-27 tags: - attack.stealth - attack.t1027.010 - attack.t1218.007 - attack.execution - attack.t1059.001 logsource: category: process_creation product: windows detection: selection_img: - Image|endswith: - \powershell_ise.exe - \powershell.exe - \pwsh.exe - OriginalFileName: - PowerShell_ISE.EXE - PowerShell.EXE - pwsh.dll selection_cli: CommandLine|contains|all: - -ComObject - InstallProduct( - .Insert( - UILevel condition: all of selection_* falsepositives: - Unknown level: high
Near-miss passage: Sigma rule: Detects a potentially suspicious execution of a process located in the '/tmp/' folder. Logsource: linux / process_creation. Rule: title: Potentially Suspicious Execution From Tmp Folder id: 312b42b1-bded-4441-8b58-163a3af58775 status: test description: Detects a potentially suspicious execution of a process located in the '/tmp/' folder references: - https://blogs.jpcert.or.jp/en/2023/05/gobrat.html - https://jstnk9.github.io/jstnk9/research/GobRAT-Malware/ - https://www.virustotal.com/gui/file/60bcd645450e4c846238cf0e7226dc40c84c96eba99f6b2cffcd0ab4a391c8b3/detection - https://www.virustotal.com/gui/file/3e44c807a25a56f4068b5b8186eee5002eed6f26d665a8b791c472ad154585d1/detection author: Joseliyo Sanchez, @Joseliyo_Jstnk date: 2023-06-02 modified: 2025-08-05 tags: - attack.stealth - attack.t1036 logsource: product: linux category: process_creation detection: selection: Image|startswith: /tmp/ filter_optional_nextcloud: Image|endswith: /usr/bin/nextcloud condition: selection and not 1 of filter_optional_* falsepositives: - Unknown level: medium