During a security assessment you may need to monitor the traffic from a Java application and also to modify it. What can you do? What if the application uses SSL/TLS and even SSL pinning? We found a very useful tool which helped us in this type of situations.
JavaSnoop is a tool developed by Aspect Security with the purpose of helping people to intercept Java function calls (e.g. toString) from Java applications. It allows you to attach to a process and intercept any Java function call, view and modify the parameter values, print the stacktrace or save all function calls to a file.
JavaSnoop allows browsing all Java classes and all functions used by the target application. What you have to do is to choose the right function from the right class to hook in order to intercept the function call and parameters. For example, you may consider functions that send, receive, hash or encrypt data in order to intercept and modify sensitive data.