Proof-of-concept Android apps that expose localhost endpoints or listeners to receive IDs from companion web payloads (HTTP, WebSocket, UDP/STUN/TURN, and mDNS) when installed on a device.

• Android Studio (Koala or newer) with Android SDK/Build-Tools 35
• Java 11+ (bundled JDK from Android Studio is fine)
• ADB with an emulator or device (API level must meet each app's minSdk; see notes below) and USB debugging enabled

.
├── StealthApp/      # NanoHTTPD HTTP server on 13380–13387 that logs headers, query params, and bodies.
├── StealthAppWS/    # WebSocket server on 12380–12387; replies with `200`` and logs text/binary frames.
├── StealthUDP/      # UDP listener on 12580 capturing incoming datagrams.
├── StealthTURN/     # Minimal STUN/TURN responder on UDP 12586 (issues nonces and allocation replies).
├── webrtc_mdns/     # Foreground service sniffing mDNS on 224.0.0.251:5353 to print WebRTC host candidates; requests Nearby devices permission on Android 14+.
├── XProfilePOC/     # Cross-profile PoC with HTTP servers on 55556/55557 storing Origin/browser metadata to demonstrate localhost abuse across profiles.
└── YandexPoC/       # HTTP servers on 29009/29010/30102/30103 logging incoming requests plus origin/browser info.

1. File → Open the desired subfolder (e.g., StealthApp/).
2. Let Gradle sync, then click Run to deploy to the attached emulator/device.

cd android-pocs/StealthApp
./gradlew assembleDebug     # build APK
./gradlew installDebug      # optional: push to the default ADB device
# APKs land in app/build/outputs/apk/debug/

Repeat in each app folder (StealthAppWS, StealthTURN, StealthUDP, webrtc_mdns, XProfilePOC, YandexPoC).

• Launch the installed app; background services start automatically and the UI shows the bound IP/ports (where applicable).
• Drive traffic from the poc-web-pages toward the exposed localhost ports listed above.
• For webrtc_mdns, tap Start to begin sniffing mDNS, Stop to release the multicast lock, and Clear to reset the log.
• XProfilePOC and YandexPoC include a history screen to review stored origins/browsers.

• HTTP/WebSocket apps write to server_logs.txt in app-internal storage and mirror entries in the on-screen log.
• UDP/STUN/TURN apps write to udp_log.txt and stream entries to the UI.
• History data for XProfilePOC/YandexPoC is kept in a local SQLite DB (logs.db).

• Apps target SDK 35; minSdk varies by project (28 for YandexPoC, 31 for webrtc_mdns, 33–34 for the others). Use an emulator/device that satisfies the app you are running.
• Ports are hard-coded; ensure they are free before launching.
• Each app runs as a foreground service; you may need to accept the persistent notification.
• webrtc_mdns needs the Nearby devices/Wi-Fi permission to capture mDNS traffic on Android 14+.