Nurech is rapidly spreading Internet worm that propagates by e-mail through messages with infected attachments. Once the user opens such an attachment, the parasite secretly installs itself to the system and runs a spreading routine. It sends bogus letters to e-mail addresses it finds in the compromised system. Then it runs a payload. Nurech terminates popular antiviruses, firewalls, some spyware removers and security-related applications. The worm has rootkit features that allow it to hide its files and processes. The parasite runs on every Windows startup.