Now here's something "new and creative!" Chinese hackers have taken a clothes iron (yes, we are talking a steam iron, see the picture) and added a small device that detects Wi-Fi networks. Once the small board (see the inset lower right) detects a public, non-password protected Access Point within 200 meters (~650 feet) it starts sending spam and malicious code.
Russian state TV program Rossiya 24 showed these irons and explained what they were doing. Here is the clip in Russian, where they they open an iron to show the "spy chip". Other products found to have rogue components reportedly included kettles, mobile phones and car dashboard cameras.
The video also showed the hidden chips had been used to infiltrate company networks. Once it was detected due to a slight increase in weight of the irons (good catch!), the latest delivery of appliances was rejected by customs, but more than 30 irons had already been delivered to retailers in St Petersburg. Wow.
Think about any piece of electronics coming from China like your coffee maker, toaster, microwave being infected with a small malicious bit of hardware. You are going to have to open up your Wireless Access Point and see what devices are connecting to it, and then track them down, perhaps using Kismet, which identifies networks by passively collecting packets and detecting (and given time, decloaking) hidden networks, and infering the presence of a beaconing device by looking at the data traffic. There may be easier ways to do this though.