Glossary
COM handler action
A scheduled task action that runs a COM object identified by a CLSID instead of an executable, usually a DLL hosted by taskhostw.exe.
The ComHandler element of the Task Scheduler schema takes a ClassId (a CLSID in braces) and optional Data. When the task fires, the service creates that COM object, typically an in-process DLL loaded in taskhostw.exe.
Many Microsoft tasks use COM handlers, so the XML shows no executable path at all. To know what really runs, resolve the CLSID under Classes\CLSID\{...}\InprocServer32 in the SOFTWARE hive. A hijacked CLSID gives persistence without creating a new task. See task XML anatomy.