Russian hackers targeting millions of devices around the world, US and UK warn

“The concern with the presence of someone on your network is are they simply there looking or as a preparatory measure for something more nefarious? Either is bad. We haven’t seen a lot of damaging attacks yet but I believe we’re going to. If they were on a transport network, for example, the potential is there to disrupt train services. You could get into the signalling network.”