Achilles is a tool for Windows designed for testing the security of web applications. Achilles is a proxy server, which acts as a man-in-the-middle during an HTTP session. A typical HTTP proxy will relay packets to and from a client browser and a web server. Achilles will intercept an HTTP session’s data in either direction and give the user the ability to alter the data before transmission. For example, during a normal HTTP SSL connection a typical proxy will relay the session between the server and the client and allow the two end nodes to negotiate SSL. In contrast, when in intercept mode, Achilles will pretend to be the server and negotiate two SSL sessions, one with the client browser and another with the web server. As data is transmitted between the two nodes, Achilles decrypts the data and gives the user the ability to alter and/or log the data in clear text before transmission.