White space padding

Whitespace padding refers to a technique wherein cybercriminals insert spaces before a filename extension to disguise the real extension of the file. Malware or grayware authors do this so that, in a fixed-width column, the extension is no longer seen and a false extension is seen instead by the user.

For example, a spam email could have a zip file called Legislation.zip attached to it, which contains a file named Legislation.doc{several whitespace characters}.exe. The whitespace padding could fool unsuspecting users to think that the attachment is a .doc file, and not an executable.