Not all data encryption is created equal

Protect your vulnerable side

Sysadmin blog I've written a recent spate of articles channelling the tinfoil hat industry that triggered some interesting conversations.

Most interesting was a debate about whether or not an organisation like the National Security Agency could take over my home network if it so chose. I suspect any decent hacker with access to the right information could cut through my home network like a hot knife through butter.

I have been doing this systems administration thing my entire working life and I could not tell you 100 per cent for sure that any of my systems are clean. I may be reasonably certain about most of them, but they are connected to the internet and I am not physically monitoring them 24/7.

Even a brief look at my home network finds a series of potential vulnerabilities that make me nervous.

Danger on the home front

Let's start with the obvious item. My network has a Wi-Fi access point. It is a Netgear device running a custom version of the OpenWRT firmware.

The OpenWRT project doesn't exactly seem to be screaming along, which means that any number of vulnerabilities in that device could be exploited if someone knew where to look.

The OpenWRT firmware running the router is essentially a Linux distribution. The radio has its own firmware as well. I don't even know how to update that.

It could have a vulnerability in it that allows a privilege escalation within the router and all of a sudden a knowledgeable attacker owns my Linux-based Wi-Fi router. There are maybe only a handful of people in the world able to do that but such attacks are not unheard of.

Similarly, there are normally five laptops, three smartphones and two tablets in my house. Each of these has a Wi-Fi and Bluetooth card; the phones and tablets have a 3G or LTE radio as well.

How many of these devices have drivers that are deep enough into the system to let an attacker get access to the kernel (assuming the right kind of bug exists)?

For that matter, how powerful are the electronics in the radios? If you could trigger a vulnerability in the firmware you might be able to load malware into the radio. I know that similar exploits have been accomplished with wired network cards.

I have a SIP phone with a wireless handset. While older wireless phones probably didn't have a small computer inside with its own firmware, operating system and so on, a SIP phone does.

So that SIP phone is yet another radio with its own firmware, drivers, operating system and so forth that could potentially house some vulnerability.

I also have a ZigBee heating and ventilation control unit; there are probably layers of ways those devices are vulnerable. The manufacturer will probably never issue a firmware update, and if it did, would I remember to check?

How powerful is that, anyway? At first glance, it is probably powerful enough to host a smallish piece of malware that could serve as a good beachhead for a broader attack against the rest of my network.

The only real defence is to turn off any devices with a radio unless you really need them

There is a pair of powerline Ethernet switches on my network for testing. It should be possible to build a device that could communicate with those things fairly easily. If someone can discover vulnerability in their firmware, then they are inside the gates and my local system network would be instantly hosed.

To be clear: the chances of a vulnerability existing, someone knowing about it and having both the skill and equipment to compromise such a device are vanishingly small. The only real defence is to turn off any devices with a radio unless you really need them. Hardware switches on laptops are a better defence than software ones.

Barring that, segment your network so that anything with a radio is isolated from everything else. Put firewalls and intrusion detection systems in place to monitor the traffic from wireless-enabled systems and allow only traffic types and destinations you know are valid.

It is not something your average consumer can do, but your average consumer wouldn't even think about the vulnerability of an IPv6 light bulb in the first place.

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