A URL verification service is provided that is used to evaluate the trustworthiness of universal resource locators (URLs). As a user browses the world wide web, a URL verification client captures a URL associated with a web page of unknown authenticity. The URL verification client transmits the captured URL to a URL verification server. The URL verification server compares the URL to actively maintained whitelist and blacklist information. The server also uses the URL and a user-supplied or automatically-extracted brand to query a search engine. The URL verification server processes the response of the search engine to the search engine queries and the results of cache and whitelist and blacklist comparisons to determine whether the captured URL is legitimately associated with the brand. The results of the URL evaluation process are transmitted from the URL verification server to the URL verification client, which notifies user.