Information security vulnerability analysis tool

Your browser should return several hits. Choose a topic which can be a tool, framework, practice, a methodology or technology related to vulnerability analysis and summarize it for the class. In your summary explain its purpose and address the following points:

1. How widely is it used?
2. How reliable is it in practice? What is its commercial availability?
3. Does it scale well? Is it applicable to networked environments?
4. Are there any other relevant aspects which you may have noticed?