This detection rule identifies when a hidden directory is created using the NTFS `::$index_allocation` stream. In NTFS, the `::$index_allocation` attribute allows files and folders to be stored in a way that makes them inaccessible to common tools like 'explorer.exe' and 'powershell.exe'. This method can be abused by attackers to create directories that may contain malicious content while hiding their presence from standard user interfaces and scripting environments. The rule captures events from the Windows operating system, specifically looking for file events where the filename contains `::$index_allocation`. It’s essential to monitor for such behavior as it can signify an attempt to conceal malicious activities. False positives are considered unlikely, making this a reliable indicator for detection purposes. The implementation of this rule aids in maintaining visibility into potentially harmful file operations on Windows systems.