In these days, security threat is ever increasing as computer systems and networking is everywhere. This paper is on the development of security scanner using search engine, with which site managers can easily check security vulnerability on their systems. Our security server automatically collects security-related information on the Internet, and indexes them in the database. To check the vulnerability of a customer server, the client system collects various system-specific information, and sends necessary queries to our security server for vulnerability checking. Up-to-date and site-specific vulnerability information is retrieved through the viewer, which allows the customer effectively to check and respond to security threat on client systems.