Insiders are an important threat to take into account, actually they are behind of a high percent of attacks suffered by companies. Networks and computers are being strongly protected against trojan infections,bots,worms,exploits and backdoors. Nevertheless, often while developing security policies,the countermeasures for detecting physical and electronic (not based on software) surveillance finally lie in a dirty,dark and sad forgotten corner.That's not ok.
Let's see briefly some notes on domestic and corporate countersurveillance measures.

From a corporate standpoint

Primary Threat: Industrial Espionage

Goal: Neutralize any attempt to leak confidential information.

Have you ever think that your meeting room can be monitorized while you are presenting your new-and-brilliant-idea which is worth its weight in gold?. There is neither anti-virus nor IDS which can detect it.

+ Maybe you are looking for a simple hidden microphone under a table. Well,it's not a big deal, take a look deeply at the room and you will catch it.

+ Maybe you are looking for a more sophisticated device inside a wall or covered by a portrait. No problem, you should use a non-linear junction (semiconductors,metals...) detector. This kind of devices can detect most of the commercial bugs.

+ Maybe you are looking for a high-tech RF,phiber optic or infra-red transmitter (not freely available for any person) device which becomes invisible for non-linear junction detectors. In those cases,RF locators, thermal or infra-red cameras are going to be your best friends.

Ok, now your meeting room is free of bugs or at least it looks like. What about your phone line?
If your line has been tapped physically, a reflectometer should spot serial or parallel bugs. Depends on the accuracy of the reflectometer you could also detect induction tappings which are not breaking the line so this kind of devices (aka "snuffle bugs") are the most difficult to detect.

Good! now your meeting is a bug free zone and you've got a clean phone access. Watch out... the window!
There are laser microphones which basically can grab a conversation firing its laser beam at the window and then the reflected beam carries the vibrations produced by the sound waves. So that it can uncover any conversation that is taking part in the room. There are several solutions, customized crystals or paints, or just a meeting room without windows :)

Cool! your meeting room is free of bugs,bugged lines and has no windows. But a room is a room,so it has at least 4 walls.
There are electronics microphones which can easily listen through a wall. It is a weird possibility but possible indeed.

From a domestic standpoint


Previous devices we have been talking about use to be very expensive since it's a professional equipment. People should not have to fortify their kitchen against a neighbor who is spying you trying to steal your secret for a tasty turkey stuff.However we are not safe at all. Far for be conspiranoics and being a realistic person there are documented cases of hidden cameras in hotels rooms, workers being observed without legal consent or thinks like that...

For those cases there are hundreds of little and cheap devices that detect RF emitters. It's a good solution. However, my suggestion is that if you are curious about this kind of things you should acquire an scanner. My scanner is an Icom IC-R3. In the european version there are not banned frequencies, unfortunately american version has some bands banned. This scanner has a novel feature, a color display. So you can visualize most of wireless cams available on the market or your favorite TV Channel.
The image you are seeing on the left is a shop with a wireless (Wideband FM) security hidden cam installed I discovered some time ago.

To be continue...