MAC address definition

A series of numbers and letters that identify a network device. MAC addresses consist of 12 characters grouped into six pairs, for example 0A:1B:2C:3A:44:5C. The MAC address is assigned to a network interface card that every connected device has. We need these addresses to be able to connect to the internet to send or receive data. As IP addresses identify a network connection, MAC addresses identify hardware. But while IP addresses change constantly, MAC addresses are static because they are only used in the local network.

MAC address tracking

The combination of Wi-Fi and the MAC address of your smartphone may inadvertently help third parties identify you. That’s because Wi-Fi-enabled devices advertise their presence so that they can connect to known Wi-Fi networks faster. They do it by sending their MAC addresses — unencrypted — whenever they’re in the range of a hotspot. As a result, anybody with a simple tracker device can monitor your presence without you noticing it.

MAC address security and privacy issues

• Privacy concerns. The MAC address of your device can be used to track your behavior, such as where and when you use it. Third parties can use this information to build a detailed profile of your activities. They can also cross-reference the MAC address with other data sources, such as social media or public records, for an even more accurate profile.
• Security risks. If a hacker gets the MAC address for any device on a network, they can impersonate its user and connect to the network as them. It’s called MAC spoofing. To obtain MAC addresses of authorized network users, hackers can use software tools such as Kismet or Ethereal.

Further reading