This detection rule identifies when a new IFilter is registered in Windows, which could indicate an attempt to achieve persistence by an attacker. The IFilter registration process is associated with Microsoft's Windows Search functionality, which allows for the indexing of various file types. By registering a new IFilter, an attacker can manipulate the indexing process, potentially extracting information from new or proprietary file formats. The rule specifically looks for changes in registry paths typically associated with IFilters, such as entries in the 'CLSID' and 'PersistentAddinsRegistered' keys. If a new registration that matches certain criteria is detected, it raises an alert.