{"id":"af5732ed-764e-489d-826d-0447c8b36242","title":"Windows MSIX Package Support Framework AI_STUBS Execution","description":"Detects execution of Advanced Installer MSIX Package Support Framework (PSF) components, specifically AI_STUBS executables with original filename 'popupwrapper.exe'.\nThis activity may indicate malicious MSIX packages build with Advanced Installer leveraging the Package Support Framework to bypass application control restrictions.\n","author":"Michael Haag, Swachchhanda Shrawan Poudel (Nextron Systems)","status":"experimental","level":"low","date":"2025-11-03","modified":"","tags":["attack.execution","attack.stealth","attack.defense-impairment","attack.t1218","attack.t1553.005","attack.t1204.002"],"technique_ids":["T1204.002","T1218","T1553.005"],"logsource":{"category":"process_creation","product":"windows"},"falsepositives":["Legitimate applications packaged with Advanced Installer using Package Support Framework"],"references":["https://redcanary.com/blog/threat-intelligence/msix-installers/","https://redcanary.com/threat-detection-report/techniques/installer-packages/","https://learn.microsoft.com/en-us/windows/msix/package/package-support-framework","https://www.splunk.com/en_us/blog/security/msix-weaponization-threat-detection-splunk.html"],"source_path":"rules/windows/process_creation/proc_creation_win_msix_ai_stub_execution.yml","source_sha256":"f83d8453e8576e833a514eafd32c728da52c8654c680b10ff2e0e0e3880a1b31","source_url":"https://github.com/anpa1200/sigma/blob/b249e9683190cffdcaf188ccbfb90bf4759844e1/rules/windows/process_creation/proc_creation_win_msix_ai_stub_execution.yml","license":"Detection Rule License 1.1","license_url":"https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md","yaml":"title: Windows MSIX Package Support Framework AI_STUBS Execution\nid: af5732ed-764e-489d-826d-0447c8b36242\nstatus: experimental\ndescription: |\n    Detects execution of Advanced Installer MSIX Package Support Framework (PSF) components, specifically AI_STUBS executables with original filename 'popupwrapper.exe'.\n    This activity may indicate malicious MSIX packages build with Advanced Installer leveraging the Package Support Framework to bypass application control restrictions.\nreferences:\n    - https://redcanary.com/blog/threat-intelligence/msix-installers/\n    - https://redcanary.com/threat-detection-report/techniques/installer-packages/\n    - https://learn.microsoft.com/en-us/windows/msix/package/package-support-framework\n    - https://www.splunk.com/en_us/blog/security/msix-weaponization-threat-detection-splunk.html\nauthor: Michael Haag, Swachchhanda Shrawan Poudel (Nextron Systems)\ndate: 2025-11-03\ntags:\n    - attack.execution\n    - attack.stealth\n    - attack.defense-impairment\n    - attack.t1218\n    - attack.t1553.005\n    - attack.t1204.002\nlogsource:\n    category: process_creation\n    product: windows\ndetection:\n    selection:\n        Image|endswith:\n            - '\\AI_STUBS\\AiStubX64Elevated.exe'\n            - '\\AI_STUBS\\AiStubX86Elevated.exe'\n            - '\\AI_STUBS\\AiStubX64.exe'\n            - '\\AI_STUBS\\AiStubX86.exe'\n        OriginalFileName: 'popupwrapper.exe'\n    condition: selection\nfalsepositives:\n    - Legitimate applications packaged with Advanced Installer using Package Support Framework\nlevel: low\n","validation":"yaml_parsed_not_backend_compiled_or_live_validated","techniques":[{"key":"enterprise/T1204.002","id":"T1204.002","name":"Malicious File","page":"techniques/enterprise/T1204.002/"},{"key":"enterprise/T1218","id":"T1218","name":"System Binary Proxy Execution","page":"techniques/enterprise/T1218/"},{"key":"enterprise/T1553.005","id":"T1553.005","name":"Mark-of-the-Web Bypass","page":"techniques/enterprise/T1553.005/"}],"data_path":"data/detection-rules/af5732ed-764e-489d-826d-0447c8b36242.json","kind":"sigma"}