It iterates over all possible Office &lt;version&gt; values for both Word and Excel &lt;product&gt; values. It then scans for documents with valid Word or Excel file extensions on all drives connected to the system. The malware moves each located document into the AppData folder, inserts malicious Word or Excel macros into it using a Microsoft.Office.Interop object, and then moves the document back into its original folder. In the samples we analyzed, the injected macros were simple downloaders