Stration.b 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. It may also open a text file containing random characters. Then Stration.b runs a spreading routine. It sends itself to e-mail addresses it gathers from local program, mail, web and text files. The worm also downloads from the Internet and executes arbitrary, potentially malicious files. It runs on every Windows startup.