Man-in-the-Middle Attacks

A man-in-the-middle (MITM) attack is when an attacker secretly places themselves between two devices that are communicating. The attacker receives the data travelling in both directions, so the two devices believe they are talking directly to each other.

For example, imagine you send a message to a friend saying "meet at 4pm". If an attacker is in the middle, they can read that message and change it to "meet at 6pm" before passing it on. Neither you nor your friend knows the message was intercepted or altered. The attacker may also tamper with the data in other ways, such as changing a file or a login request, without either party knowing.

Reducing the risk

Encryption scrambles data so that it becomes unreadable without the correct key. It does not stop an attacker intercepting the data, but it stops them being able to decode and read it, so anything they capture is useless to them.

A VPN (virtual private network) creates an encrypted tunnel between your device and the VPN server. Even if your data is intercepted, it cannot be decoded and read. Both measures therefore make a man-in-the-middle attack harder to carry out successfully: the attacker may still capture the data, but it is useless to them.