Android Bluetooth Mac Address Change

Google releases a fix for the security hole that, if left unplugged, could allow attackers to run malicious code with no user interaction

Google has rolled out a security update to address a critical flaw in Android’s Bluetooth implementation that allows remote code execution without user interaction.

以上、MacとAndroidスマホ間をBluetooth接続でファイル共有をする方法でした。前述の通り、特別なソフトをインストールする必要がない、データ転送量を節約できるなどがこの方法の利点ですね。. A tiny window will open up to show your mac address. Note: This trick may not work on some Android phones. For example, it doesn’t work on my Samsung device. Use a MAC address finder app. If you frequently need to look for the MAC address of your Android phone, then using a. Step-by-step guide for importing apps from Android to Mac. Step 1: Make sure to install and launch the latest version of Dr.Fone Toolbox on your Mac. On the Dr.Fone interface tap the ‘Transfer’ tab first. Now, take a USB cable and then connect your Mac and Android phone together. Connect your Mac with a Bluetooth keyboard, mouse, trackpad, headset, or other audio device. Make sure the device is turned on and discoverable (see the device’s manual for details). On your Mac, choose Apple menu System Preferences, then click Bluetooth.

The vulnerability, tracked as CVE-2020-0022, affects devices running Android Oreo (8.0 and 8.1) and Pie (9.0). For these devices, which between them account for almost two-thirds of Android devices in use, the flaw is rated critical by Google.

According to German IT security provider ERNW, which discovered the ‘wormable’ security hole and reported it to Google three months ago, the bug could be exploited to pilfer personal data or distribute malware. Attackers could “silently execute arbitrary code with the privileges of the Bluetooth daemon”, said the company.

“No user interaction is required and only the Bluetooth MAC address of the target devices has to be known. For some devices, the Bluetooth MAC address can be deduced from the Wi-Fi MAC address”. Obviously attackers also need to be within close proximity of the targeted device and the phone or tablet has to be in discoverable mode.

The bug is much less of a problem for Android 10, where it cannot be exploited and leads ‘only’ to a crash of the Bluetooth daemon. Android versions older than 8.0 were not tested.

ERNW stopped short of describing the bug in detail or sharing proof-of-concept code, as it waits for the fixes to reach end users.

Patch me if you can

If you own a Google-branded smartphone such as Pixel, you’re in luck. By contrast, patching may not be as fast as desired for many other Android device owners, who need to wait for their phone manufacturers or carriers to roll out the updates. Worse, many devices may no longer be supported.

Google, which included the fix in its latest assortment of monthly security updates for Android, said that it notified all Android device makers of the issue at least a month ago.

One way to lessen the risk is ensure that your phone is in non-discoverable mode when Bluetooth is on. Alternatively, enable Bluetooth only if necessary and remember to turn it off when not in use.

Discussion

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Starting in Android 8.0, Android devices use randomized MAC addresses when probingfor new networks while not currently associated with a network. In Android9, you can enable a developer option (it'sdisabled by default) to cause the device to use a randomized MAC addresswhen connecting to a Wi-Fi network.

In Android 10, MAC randomization is enabled by defaultfor client mode, SoftAp, and Wi-Fi Direct.

MAC randomization prevents listeners from using MAC addresses to build a historyof device activity, thus increasing user privacy.

Additionally, MAC addresses are randomized as part ofWi-Fi Aware andWi-Fi RTT operations.

Implementation

To implement MAC randomization on your device:

Work with a Wi-Fi chip vendor to implement the following HAL methods:
- IWifiStaIface#setMacAddress: Configures the MAC address of theinterface. The default implementation brings the interface down, changesthe MAC address, and brings the interface back up.
- IWifiStaIface#getFactoryMacAddress: Gets the factory MAC of wlan0using an ioctl call.
- ISupplicantP2pIface#setMacRandomization: Sets P2P MAC randomizationon/off in the supplicant.
Setconfig_wifi_connected_mac_randomization_supported to true in the Settings config.xml (this can be done in a devicecustom overlay).
- This flag is used to control whether client-mode MAC randomization isenabled.
Setconfig_wifi_p2p_mac_randomization_supported to true in the Settings config.xml (this can be done in a devicecustom overlay).
- This flag is used to control whether Wi-Fi direct MAC randomization isenabled.
Test your implementation using the methods described inValidation.

The System UI must:

Have an option to enable or disable randomization for each SSID.
Have MAC randomization enabled by default for all newly added networks.

Use thereference implementation of Settings UI to implement new prompts.

Devices running Android 9 or lower might not havesupport for Wi-Fi MAC randomization. When upgrading such devices to Android10, the Wi-Fi MAC randomization feature can be disabledby setting the WIFI_HIDL_FEATURE_DISABLE_AP_MAC_RANDOMIZATION flag to true inthe Wi-Fi vendor HAL make file.

Validation

To validate that the feature is working as intended, run both an integrationtest (ACTS) and a manual test.

To run an integration test, use the ACTS file,WifiMacRandomizationTest.py, located intools/test/connectivity/acts/tests/google/wifi, to verify that the device usesthe randomized MAC address and correctly stores the randomized MAC address foreach network.

To run a manual test:

Verify that MAC randomization is enabled on the device by checking thatconfig_wifi_connected_mac_randomization_supported is set to true in thedevice overlay.
Connect to a Wi-Fi network.
Tap the network to go to the Network details page. Verify that MACrandomization is turned on. Verify that the MAC address displayed is arandomized MAC, which has the locally generated bit set to 1 and themulticast bit set to 0.
Turn MAC randomization off. Connect to the same network and verifythat the factory MAC is being used.
Delete the network by tapping Forget on the Network details page.
Connect to the same network and verify that the same randomized MACaddress is being used.
Note: Randomized MAC addresses are generated per SSID and are persistent.

To test MAC randomization on a pre-Android 10 device(capable of supporting MAC randomization) upgrading to Android10 or higher:

Have at least one saved network on a device runningAndroid 9 or lower.
Flash the Android 10 system image.
In the Wi-Fi picker, verify that MAC randomization is turned off for allsaved networks.
Turn MAC randomization on. Connect to the same network and verifythat the randomized MAC is being used.

Note:

Android Bluetooth Mac Address Change

You may experience up to a three-second delay when connecting to anetwork due to the driver flushing saved scan results when theinterface goes down. If this is the case, check with your siliconpartners to resolve the issue.

Android Bluetooth For Mac