Embedded (E)GPRS/EDGE, 3G, 4G, and 5G modules are commonly used for a lot of purposes. Indeed, we can find them in connected devices such as intercoms, alarms, automotive ECUs, In-Vehicle Infotainment (IVI) Systems, rental cars' unlocking boxes (e.g: Getaround connect unlocking system that uses Bluetooth LE but also a backup mobile connection), etc. During the lockdown, PentHertz accidentally found vulnerabilities in the device management process of some modules that could lead an attacker to backdoor FOTA updates of modules remotely at scale. This quick blog post introduces mobile modules, the FOTA attack vector, and different vulnerability classes that could be found to target several modules of other vendors. Considering the risks of these threats, we also encourage all mobile module vendors we did not get the chance to contact us at [email protected] to check modules and the user device management process security and help them to fix identified or new vulnerabilities.