OWASP Mobile Top 10 — M5: Insecure Communication

Welcome to the fifth article in our OWASP Mobile Top 10 2024 series! In previous articles we covered M1: Improper Credential Usage, M2: Inadequate Supply Chain Security, M3: Insecure Authentication/Authorization, and M4: Insufficient Input/Output Validation. Today we discuss why "we already use HTTPS" isn't a sufficient answer. Introduction M5 is the most misleading item on the list, because most teams read it and move on: "We use HTTPS, this doesn't apply to us." OWASP's definition is far broader. This risk covers all aspects of getting data from point A to point B, but doing it insecurely. It encompasses mobile-to-mobile communications, app-to-server communications, or mobile-to-something-else communications. It includes all communications technologies that a mobile device might use: TCP/IP, WiFi, Bluetooth/Bluetooth-LE, NFC, audio, infrared, GSM, 3G, SMS, etc. So M5 isn't just "do you use HTTPS." It's all of this: Whether you set up TLS correctly (certificate checking, cipher selection) Whether your traffic is consistent (some endpoints HTTPS, others not) What your third-party SDKs are doing What your WebView is loading What you send over alternate channels like push notifications and SMS 💡 Key point: Just because an app uses transport security protocols doesn't mean it's implemented correctly. HTTPS is not a checkbox; it's a system that must be configured properly. A specific situation for React Native developers In React Native the network layer lives in three separate places, and most developers only think about the first: The JavaScript side — fetch , axios , XMLHttpRequest Platform configuration — ATS on iOS, Network Security Config on Android Native modules and SDKs — analytics, ads, crash reporting, payment SDKs Whatever you do on the JavaScript side, if platform configuration is loose or a third-party SDK uses plaintext HTTP, your app is exposed. OWASP Assessment Metric Value Meaning Exploitability EASY A proxy and the same network is enough Prevalence CO