Potential Serious Security Flaw with BT Smarthub 2

[jonkendall]

My neighbour and I have the same setup, full fibre and smarthub 2.

But out broadbands are connected together somehow.  I have had engineers from BT and OpenReach and noone can work out how this has hapended.

Basically my neighbour and I have never exchanged WiFi passwords yet I can see his routers admin page and make changes on it (like turning the light on his router on an off) and he can see mine.

It is not wifi because I have connected to my router using an ethernet cable and the same happens.

This means the 2 routers are talking to each other and can create a tunnel between them. 

This is potentially a massive security flaw as I could see what he is doing and he could see what I doing with no encryption whatsoever.

This looks like a serious flaw in the BT Smarthub 2 software and something that needs to be addressed urgently.

[licquorice]

I suspect one or both of you are using powerline adapters.

[jonkendall]

OK.  Why?

[imjolly]

similar problems have been posted before and the cause was found to be powerline adapters probably in adjoining wall

[jonkendall]

I have a powerline adaptor for BT TV which BT supplied.  I have to because I have Fibre broadband and the fibre has to be by the front door and the tv is in the lounge and this requires a wired connector.

[jonkendall]

Yes it is an adjourning wall?  So are you saying the powerline adaptor is basically "hopping" onto my neighbour's ringmain?

[licquorice]

Yes.

Easily proved, remove adapter temporarily.

[WSH]

Most powerline adapters have for encryption.  You may be able to change the key.  If you and your neighbour are still using the default key they will be able to talk to each other.  It's a "flaw" that's been well known for over 10 years and works through the shared mains supply.

[jonkendall]

Unplugged it now.  Great that BT who supplied the powerline adaptor don't seem to know about this.

[jonkendall]

When you say shared mains supply, this is a modern house with 100A supply so would it be "shared".  Are you saying that everyone on the same single phase as me could potentially have this issue, or is it that because my neighbour and my ringmains are either side of the same wall we are getting "interference"