Certificate information associated with a received certificate, such as a Secure Sockets Layer (SSL) certificate is stored in a trusted local cache and/or in one or more remote trusted sources, such as a single remote trusted source and/or a trusted peer network. When a site certificate is received on a host computer system, certificate information associated with the received site certificate is obtained and compared with the stored certificate information to determine whether or not the site certificate indicates malicious activity, such as a malicious DNS redirection or a fraudulent local certificate. When a site certificate is not found indicative of malicious activity, the site certificate is released. Alternatively, when a site certificates is found indicative of malicious activity protective action is taken. In some embodiments, a user's log-in credentials are automatically obtained from a trusted local cache and automatically submitted to a web site.