There is an ever increasing concern about security threats as embedded systems are moving towards networked applications. Model based approaches have proven to be effective techniques for embedded systems design. However, existing modeling tools were not designed to meet the current and future security challenges of networked embedded systems. In this paper, we propose a framework to incorporate security modeling into embedded system design. We’ve developed a security analysis tool that can easily integrate with existing tool chains to create co-design environments that addresses security, functionality and system architecture aspects of embedded systems concurrently.