Re: [Zephyr-devel] How hacker will hack/impact my BLE device, when ...??

Vikrant More <vikrant8051@...>


MITM attacks are when a third device, which we will call the malicious device, impersonates the other two legitimate devices, in order to fool these devices into connecting to it. In this scenario, both the GAP Central and GAP Peripheral will connect to the malicious device which in turn routes the communication between the two other devices. This gives the legitimate devices the illusion that they are directly connected to each other when in fact their connection has been compromised. This setup not only allows the malicious device to intercept all the data being sent, but also allows it to inject false data into the communication or remove data before it reaches its intended recipient.


After reading this, I understand that without OOB Pairing everything is more or less insecure.

On Wed, Mar 21, 2018 at 7:04 PM, Marcio Montenegro <mtuxpe@...> wrote:
Google Secure beacons.No new hardware design :


On Wed, Mar 21, 2018 at 10:15 AM, Vikrant More <vikrant8051@...> wrote:
Hi Marcio,
I'm not allowed to add anything extra in my current hardware design.

Besides this, is there any thing which is very serious ?
I'm still trying to understand various security risk behind my current implementation.


On Wed, Mar 21, 2018 at 5:35 PM, Marcio Montenegro <mtuxpe@...> wrote:
Hi all,
Maybe you can use crypto device on your product.

You also need to develop an application to configure  crypto device chip.
Then after configuration each device are unique.
For inspiration see:

Note that this devices has no Bluetooth.

On Wed, Mar 21, 2018 at 2:08 AM, Vakul Garg <vakul.garg@...> wrote:

Hi Vikrant


I am curious to understand about your security implementation.

I work in area of TLS security and I am not bluetooth security expert.


In your case, does the app need to differentiate between a genuine or fake device?

Will it be able to create a shared secret with the device even if it is a clone of genuine device and purpose programmed to leak the common encryption key?






From: zephyr-devel-bounces@... [mailto:zephyr-devel-bounces@...] On Behalf Of Vikrant More
Sent: Tuesday, March 20, 2018 11:28 PM
To: zephyr-devel@...; zephyr-users@...
Subject: [Zephyr-devel] How hacker will hack/impact my BLE device, when ...??




In my current project, I haven't implemented OOB pairing ( BLE based smart lights)


Using Zephyr built-in ECDH library, shared secret (using secp256r1 curve) get created on Device as well as on APP side which will act like encryption key for further communication.


On that encrypted link, APP send encryption key which is common for all devices associated with it.


All this happens when DEVICE is in factory reset mode.


There after communication link is encrypted using newly assign common key.




This will create security risk, only if device is not authenticated by user & it could transfer security key ( which is common to many devices) to unauthorized device.


To solve this, APP will automatically trigger DEVICE's LEDs to blink & ask user "do you see blinking LED?" 


If user click on "YES" then & only then ECDH process will initiate & common key get share with new DEVICE.




Besides this I didn't found any security flaw in this implementation. So I need help from Bluetooth Security expert. Is there anyone who can help me to find out flaws & security risks in my current implementation ?




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