Techniques
Sample rules
Windows Advanced Installer MSIX with AI_STUBS Execution
- source: splunk
- technicques:
- T1218
- T1553.005
- T1204.002
Description
The following analytic identifies the execution of Advanced Installer MSIX Package Support Framework (PSF) components, specifically the AI_STUBS executables with the original filename ‘popupwrapper.exe’. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process paths and original filenames. This activity is significant as adversaries have been observed packaging malicious content within MSIX files built with Advanced Installer to bypass security controls. These AI_STUBS executables (with original filename ‘popupwrapper.exe’) are hallmark artifacts of potentially malicious MSIX packages. If confirmed malicious, this could allow attackers to execute arbitrary code, establish persistence, or deliver malware while evading traditional detection mechanisms.
Detection logic
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes where Processes.process_path IN ("*\\AI_STUBS\\AiStubX64Elevated.exe", "*\\AI_STUBS\\AiStubX86Elevated.exe", "*\\AI_STUBS\\AiStubX64.exe", "*\\AI_STUBS\\AiStubX86.exe") AND Processes.original_file_name="popupwrapper.exe" by Processes.action Processes.dest Processes.original_file_name Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product
| `drop_dm_object_name("Processes")`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_advanced_installer_msix_with_ai_stubs_execution_filter`