Computer security "incidents" occur with alarming frequency. The incidents range from direct attacks by both hackers and insiders to automated attacks such as network worms. Weak system controls are frequently cited as the cause, but many of these incidents are the result of improper use of existing control mechanisms. For example, improper access control specifications for key system files could open the entire system to unauthorized access. Moreover, many computer systems are delivered with default settings that, if left unchanged, leave the system exposed. This document discusses automated tools for testing computer system vulnerability. By analyzing factors affecting the security of a computer system, a system manager can identify common vulnerabilities stemming from administrative errors. Using automated tools, this process may examine the content and protections of hundreds of files on a multi-user system and identify subtle vulnerabilities. By acting on this information, system administrators can significantly reduce their systems' security exposure. This document examines basic requirements for vulnerability testing tools and describes the different functional classes of tools. Finally, the |