Stration.d is an Internet worm that spreads by e-mail through messages with infected attachments. Once the user opens such an attachment, the parasite installs itself to the system. Then it runs a spreading routine. Stration.d sends itself to e-mail addresses it gathers from the Windows Address Book and local program, mail, web and text files. The worm also downloads from the Internet and executes arbitrary, potentially malicious files. Stration.d runs on every Windows startup.