In recent years, increase in the development of connected and autonomous vehicles (CAVs) has sparked cyber security concerns. In particular, vehicle-to-everything (V2X) communication, which is essential for CAV and the transportation system, has introduced a new threat landscape and created several attack surfaces for malicious agents. The available literature on cyber-attacks mostly concentrate on sophisticated tools and equipment in performing malicious activities. However, ignorance of simple attack and defense methods, sometimes as simple as defining proper access policies, is among top reasons for cyber-attacks. This paper aims to emphasize on the need for practicing security-bydesign and increase awareness of manufacturers and developers to adopt minimum security measures. A generic network communication vulnerability assessment method is adopted to perform navigational attack through GPS falsification on connected vehicles, using an Unmanned Ground Vehicles (UGV) as a case study. This paper underlines the Wi-Fi security threats if used for V2X communication without proper access control measures in place. The experimental analysis demonstrates exploitation of a vulnerability which allows full control and backend navigation manipulation with respect to the UGV movement.