Gromozon is an extremely dangerous trojan illegally installed to victim computers by malicious web sites through sophisticated exploits. This parasite is a hard to get rid of threat that integrates downloader trojans, rootkits, adware and other dangerous pests. Once installed, Gromozon secretly downloads from the Internet and drops numerous malware parasites that serve unsolicited commercial advertisements, change essential system settings, severely degrade system performance, decrease Internet connection throughput, create malicious system services, etc. They can also crash the compromised computer and corrupt the entire system. Gromozon uses advanced rootkit techniques to hide its files, registry keys and related objects. It also injects malicious code into running software and system processes in order to make its removal as much difficult as possible. Gromozon runs on every Windows startup. It should be noted that web sites distributing Gromozon are hosting exploits targeting all popular web browsers (Microsoft Internet Explorer, Mozilla Firefox, Opera).