A key challenge for the use of unmanned aerial vehicles (UAVs) is the security of their information during navigation to accomplish its task. Information security is a known issue, but it seems to be overlooked from a research perspective, that tends to focus on more classical and well-formulated problems. This paper addresses an experimental evaluation of three Denial of Service (DoS) attack tools to analyze the UAV's behavior. These tools are executed in real-time on the robot while it navigates an indoor environment (inside the University building). We present experiments to demonstrate the impact of such attacks on a particular UAV model (AR.Drone 2.0) and also show a description of existing vulnerabilities. Our results indicate that DoS attacks might cause network availability issues influencing critical UAVs applications, such as the video streaming functionality.