Security is a big issue and all too often it is only thought of as it applies to the network administrator. However, programmers face a host of threats to their applications. The solution is to build a threat model. The purpose of a threat model is to aid in identifying potential threats before a system is built, not after. This talk will cover some of the common threats to applications and how to prevent them. This talk is based upon Microsoft's Threat Analysis and Modeling (TAM) tool which is free.