About IntelliScan

Rather than relying on the filename alone, IWSVA uses IntelliScan to identify the true file type, and whether it is a type that IWSVA should scan.

• True File-type Detection—IntelliScan first examines the header of the file using true file-type identification and checks if the file is an executable, compressed, or other type of file that could be a threat. IntelliScan examines all files to be sure that the file has not been renamed—the extension must conform to the file's internally registered data type.
  
  For example, Microsoft Word documents are file extension independent, even if you rename a document from "legal.doc" to "legal.lgl," Word still recognizes and opens the document, along with any macro viruses it contains. IntelliScan identifies the file as a Word document regardless of the file extension, and scans it accordingly.
   

• File Extension Checking—IntelliScan also uses extension checking, that is, the filename itself. The list of extension names to be scanned is updated with each new pattern file. For example, when there was a new vulnerability discovered with regard to ".jpg" files, the ".jpg" extension was immediately added to the extension-checking list for the next pattern update.