NSA whistleblower Edward Snowden told lawyers he met during his sojourn in Hong Kong to put their cell phones in his fridge to thwart any eavesdroppers.

But new research suggests he should have been worried about nearby TVs, too.

Smart tellies with built-in microphones and storage can be turned into bugging devices by malware and used to record conversations, security experts at NCC Group said. And they demonstrated exactly that just down the road from the Infosec Europe conference, held in London.

"Installing the bugging software requires physical access to the device, which is how we did it, or by installing a malicious app," said Felix Ingram, principal consultant at NCC Group.

"Malicious apps could be downloaded from the manufacturer’s app store. The TV does have the option for auto-updating, so releasing a legitimate app, then releasing a malicious update, is another attack vector."

In other words, Ingram's research shows smart TVs can be abused in much the same way that dodgy apps on Android software stores hijack smartphones and tablets.

In the NCC demo, the internal storage of a smart TV was used to hold 30 seconds of audio, but a far longer buffer could be set up. The main limitation of the attack is getting malicious code onto vulnerable devices in the first place, as Ingram noted.

"The devices contain microphones and cameras that can be utilised by applications, Skype and similar apps being good examples," Ingram told El Reg.

"The TV has a fairly large amount of storage, so would be able to hold more than 30 seconds of audio – we only captured short snippets for demonstrations purposes. A more sophisticated attack could store more audio locally and only upload it at certain times, or could even stream it directly to a server, bypassing the need to use any of the device’s storage.

TV builders have released source code that makes developing malware a little easier

"There is nothing specific about them running Linux that makes the hacking any easier, though some manufacturers have released some of their source code, which could make developing applications for the devices a little easier."

The smart TV hacking was part of a demonstration by NCC experts to highlight security shortcomings on the home front of the Internet of Things. Broadband routers and Wi-Fi-controlled power plugs were also attacked, and a smartphone with NFC wireless radio was used in an attempt to clone a hotel room access card.

Whatever cryptography was used by the hotel system, it was able to thwart the cloning software, thankfully.

The Wi-Fi plugs came with a default password, but without clear instructions on how to change this: users have to download and run an executable to do this, but the software presents an alarming warning that any cock-ups will brick the device.

"To update or change the firmware is too complicated," noted Paul Vlissidis, technical director of NCC Group, in something of an understatement.

Software vulnerabilities and weak configurations made it easy for NCC staffers to break into home routers. Folks using compromised broadband gateways could be directed to servers under the control of crims, allowing the crooks to intercept sensitive e-banking or webmail usernames and passwords, for instance.

As for internet-connected coffee makers and such gear, compromising that kit provides a stepping stone into a home network for a criminal. Seemingly innocuous devices can be chained together to attack the home of the future, we were told.

Net-connected devices are designed with price and functionality in mind rather than security, it seems. "Interoperability trumps security every time," Vlissidis concluded. ®