Smart Pet Collar Turns Cats into Wi‑Fi Hacking Tools at DEF CON

At the end of July, in the suburbs of Washington, D.C., a Siamese cat named Coco roamed the neighborhood. It spent three hours traversing the backyards of nearby neighbors. It killed a mouse and proudly brought the dead mouse back to the home of its 80-year-old owner, Nancy. While Coco was wandering outside, it also investigated the wireless routers of nearby neighbors, discovering that four of the routers were old and easy to crack, and another four had no password at all.

Coco was unaware that the collar around its neck was designed by Nancy's son-in-law, security researcher Bransfield. Bransfield installed a Spark Core chip inside the collar, containing his custom firmware, a Wi-Fi card, a miniature GPS module, and a battery. For detecting neighbors' Wi-Fi networks, understanding which homes are fully vulnerable to intrusion and which can be cracked with simple tools, these tools are necessary.

Cat Skitzy

Although his presentation topic at this hacker conference was 'How to Arm Your Pet,' Bransfield believes the smart pet collar poses no potential security threat. On the contrary, this fun design is intended to entertain the hacker audience at the conference. However, the data brought back by the cat shows that many wireless networks are still using the easily crackable WEP encryption from over a decade ago, which surprised him. 'My goal is not to let people know where free Wi-Fi is; I just think it's fun to put detection technology on a cat and let it roam around,' Bransfield said. 'The data the cat obtained shows that even though it's now 2014, many people still have open networks or use outdated encryption methods.'

In his talk, Bransfield will explain how to make a smart pet collar, and people can imitate him to create their own Wi-Fi detecting cat. This device only became feasible recently because the Spark Core was improved last month, making it easier to program. Earlier, someone had shown him a GPS pet collar that emits signals to locate pets at a security briefing, which gave Bransfield the idea of using a cat for wireless detection. 'All you need is a Wi-Fi detector,' he said, 'This idea is interesting, so I decided to build one.'

In the initial experiment, he placed an HTC Wildfire smartphone in the pocket of a pet jacket and had his colleague's large cat Skitzy wear it. However, Skitzy quickly shook off the jacket and lost Bransfield's device. 'Too bad,' he said, 'That cat owes me a phone.'

Smart Collar and Dollar Size Reference

Over the next few months, Bransfield devoted all his energy to building the collar. Nancy helped him sew the components into a fabric strap, then placed it on Skitzy for testing. However, Skitzy disappointed him: the cat sat on the front porch motionless until the battery ran out.

In fact, Coco proved to be an excellent spy cat. Over about three hours, it detected 23 Wi-Fi points, finding that one-third were completely open or used easily crackable encryption. Bransfield mapped these network points using the Google Earth application programming interface (API), and the number of sites with weak security protection was astonishing. Bransfield said that several Wi-Fi routers still retained their factory settings.

Although Bransfield and his cat detective mainly did this for self-amusement, he also hopes to raise more people's security awareness—even though the security community has long taken encryption for granted. 'It's clear that, relative to network security, people are more interested in cats,' Bransfield said. 'If we can let everyone know that even a cat can break into their home Wi-Fi network, that might not be a bad thing.'