R.: Fraudulent and malicious sites on the web

Fraudulent and malicious web sites pose a signicant threat to desktop security, integrity, and privacy. This paper examines the threat from dierent perspectives. We harvested URLs linking to web sites from dierent sources and corpora, and conducted a study to examine these URLs in-depth. For each URL, we extract its domain name, determine its frequency, IP address and geographic location, and check if the web site is accessible. Using 3 search engines (Google, Yahoo!, and Windows Live), we check if the domain name appears in the search results; and using McAfee SiteAdvisor, we determine the domain name's safety rating. Our study shows that users can encounter URLs pointing to fraudulent and malicious web sites not only in spam and phishing messages but in legitimate email messages and the top search results returned by search engines. To provide better countermeasures against these threats, we present a proxy-based approach to dynamically block access to fraudulent and malicious web sites based on the safety ratings set by McAfee SiteAdvisor