The speakers used publicly available information, such as IP addresses, to map out the office space and gain unauthorized access. They were able to walk around freely and even enter the employee break room without being challenged for not wearing badges.
NAC is a security solution that restricts network access based on a device's MAC address. This technology allows for better network control and security.
Jeremiah was able to bypass network access by changing the MAC address on his computer to match that of the printers on the same network.