Amirecivel.b, also known as Amircivil.b, is a worm that spreads through file sharing networks using the Kazaa peer-to-peer client. Once executed, the parasite installs itself to the system, creates multiple copies of itself, and shares infected files with users of file sharing networks. Amirecivel.b hides windows of running security-related programs and other installed software. It also deletes some library (.DLL) files and blocks access to popular Internet resources including some well-known security-related web sites. The worm runs on every Windows startup.