BestCleaner.us is a hijacker of the notorious rogue anti-spyware called System Security (or SystemSecurity, System Security 2009), which relies on misleading advertising to sell its “full version”. BestCleaner.us hijacks the victims’ browsers through the use of Trojans that creep into the target system and modify browser configuration. BestCleaner.us offers its visitors an online system scan that reports pre-determined fake results. On BestCleaner.us, you may also get some pop-up alerts which create the illusion that your system is infected. This is the way BestCleaner.us pushes a user into purchasing the full version of System Security. BestCleaner.us is a malicious website and should be avoided at all cost. Remove any programs associated with this website as soon as you detect them.