Quarantine periods longer than anticipated working lifetimes for phishing websites are used to protect users from phishing attacks. A central server or the like receives data indicating user attempts to submit confidential information to websites from a plurality of user computers. The received data is aggregated, and used to track website activity concerning solicitation of confidential information. The central server acquires and maintains current statistical data concerning phishing website lifetimes. The aggregated data concerning attempts by users to submit confidential information to websites and the current statistics concerning phishing website lifetimes are used to determine appropriate quarantine periods for websites, which can be enforced when users try to transmit confidential information to these websites.