Messaging applications Messenger, Signal, and Telegram exhibit significant differences in permissions and operational behaviors that impact user privacy. Telegram has the fewest total permissions at 71, with 25 classified as dangerous; Signal requests 72 permissions, including 19 dangerous ones; and Messenger requests the most at 87, with 24 dangerous permissions. Messenger also has the highest number of vendor-specific unknown permissions. Access to sensitive resources is crucial for messaging functionalities, with permissions for contacts, camera, microphone, location, storage, and calendar being essential. Telegram and Messenger request additional system-level permissions, while Signal is more conservative and does not request certain permissions like phone-call control or overlay windows.
The analysis, using the Mobile Security Framework (MobSF), indicates all three apps are in the medium risk category, with Messenger having more flagged issues. Telegram allows cleartext connections by default, potentially exposing traffic, while Signal uses encrypted connections by default and only permits limited cleartext traffic for certificate checks. Messenger's issues include world-writable files and remote debugging enabled in WebViews. Messenger uses third-party SDKs, while Signal and Telegram do not disclose third-party trackers. All three utilize Firebase Cloud Messaging for notifications without sensitive data leakage. Data exchange patterns show Messenger primarily routes traffic through North America, while Telegram and Signal focus on Europe with some additional connections in the U.S. and Asia.