Connecting a Phone

Connecting a phone

Every apex device … command talks to the phone over ADB (Android Debug Bridge), as the non-root shell user. Nothing is installed on the phone.

Prerequisites

On the phone	Why
Unlocked (the owner's code)	to enable USB debugging and accept the computer's key; Android also refuses some reads while locked
Developer options enabled	Settings → About phone → tap Build number (MIUI: MIUI version) 7 times, then enter the code
USB debugging on	Settings → System → Developer options → USB debugging (MIUI: Additional settings → Developer options)
A data cable	a charge-only cable shows no device at all

On the computer	Why
No adb server running	it holds the USB interface: adb kill-server
Linux: udev rules installed	see Installation

Enabling developer options and USB debugging changes the phone's settings: note it in the procès-verbal (see Field procedure).

First connection

1. Plug the phone in and run any device command, for example apex device listen.
2. On the phone, accept Allow USB debugging? and tick Always allow from this computer.
3. APEX creates its key at ~/.android/adbkey on first use (the same path as adb), so the prompt appears only once per phone. If the phone has not answered after a few seconds, APEX says it is waiting.

If the phone asks for a USB mode, choose File transfer. Some phones only show the debugging prompt in that mode.

apex device listen                  # waits, then prints "Device connected (SERIAL)"
apex device listen --timeout 60     # give up after 60 s (exit code 1)

Several phones

apex device listen prints every connected serial. Pick one with --serial <SERIAL> on any device command:

apex device acquire --serial LJSKNB6HTKVSOVJF -o ./case-42

Without --serial, APEX refuses to guess when more than one phone is plugged in.

Over the network

Legacy ADB over TCP, unencrypted. Only on a network you control.

1. Connect the phone over USB once and switch ADB to TCP with the Android platform tools: adb tcpip 5555 (APEX has no command for this step), then adb kill-server.
2. Unplug, find the phone's IP address (Settings → Wi-Fi → network details).
3. apex device acquire --tcp 192.168.1.20 -o ./case-42 (port 5555 by default, or HOST:PORT).

Android 11+ Wireless debugging (pairing code, TLS) is not supported.

A custom ADB key

--adb-key <PATH> uses another private key, for example a key per examiner or per case. The phone asks for authorization again for a new key.

Before you start an acquisition

• The phone should stay unlocked and awake during an acquisition: set the screen timeout to the maximum, or keep touching it. A locked phone answers most commands but refuses some.
• Keep it charged (an acquisition records the battery level at reception).
• Isolate it from the network as soon as the remote-wipe check allows (see Field procedure): airplane mode, or a Faraday bag with the cable through a filtered port.

See Troubleshooting if the phone is not found or the connection fails.