In a perfect example of how public wireless networks can be dangerous for privacy and security, an Israeli hacker showed that he could have taken over the free Wi-Fi network of an entire city.

On his way home from work one day, Amihai Neiderman, the head of research at Israeli cybersecurity firm Equus Technologies, spotted a wireless hotspot that he hadn’t seen before. What made it unusual was that it was in an area with no buildings.