Testing Flex applications (II)
In the previous post we manage to extract some information from the SWF file and understand the structure of the important part in a Flex application. In this chapter we are going to automatize the process of extraction and analysis.
If you are sharp-eyed you probably saw the “deblaze” name in the past post screenshots. This is the name of the first tools we are going to use today and can be found in the deblaze website. You can also found some great examples about the use of the tool.
The first step to analyze with deblaze a SWF application is execute deblaze with the -f parameter, passing the swf URL.
Sometimes deblaze is able to determine the gateway technology but in this case it doesn’t work. Also deblaze is falling detecting the Service name. Why? Well, we have, in this case, access to the source code and we can determine that the service name is Players_service:
This is because deblaze is extracting the information from the XML that we see in the last post. In this file is referenced the zendamf service, but the real one is Players_service. If we don’t have access to the source code we can make a quick search at the swf bytecode:
Also we can see the name of the methods the players_Service is offering to the users. Each method require some parameters that we can also found reading the bytecode.
This parameters can be simple objects like integers, booleans or strings but also can be more complex data as custom objects. In this case the parameter send with the add_Player method is a PlayerVO object. To analyze this object we have the possibility to analyze (again) the swf code to get the data.
This, of course, can be inferred by the possibility to analyse the living app to generate the add_Player action and catch the request using a local proxy tool. Charles Proxy has the ability to show clear text AMF messages between the server and the application.
As you can see Charles Proxy shows us the name of the service, the method and the parameters that the swf file is sending to the gateway. Using this tool and navigating for the web page we can generate a tree of request that will expose mostly all the request that the application has defined.
This way to analyze the application is less painful but we can also miss some important (or administrative) function that is not accessible for a normal user. We recommend do both for a better understanding of the whole application.
Flex gateways can be requested from outside the swf file and in the next post we will cover how to generate fake request to test the server.