Sixem, also known as Deza, is an Internet worm that spreads by e-mail through messages containing information regarding the FIFA World Cup. Those letters arrive with infected executables attached. Once the user opens such an attachment, the parasite secretly installs itself to the system and runs a spreading routine. It searches text and spreadsheet documents, web and e-mail client files for e-mail addresses. Then it sends out numerous e-mail messages to gathered addresses. Sixem’s payload is comprised of several harmful functions. The worm terminates running antiviruses, firewalls, system tools and other security-related applications. It also downloads from the Internet and runs malicious files. Furthermore, it transfers gathered e-mail addresses to remote servers. The worm runs on every Windows startup. It is able to remove itself from the system.