What is man-in-the-middle attack, how to prevent man-in-the-middle attack?

Man-In-The-Middle attack is the kind of attack used by attackers to step into an existing connection to get the exchanged data and insert false information. The steps of this attack include eavesdropping on a connection, intruding into a connection, intercepting messages, and selectively modifying data.

How to prevent man-in-the-middle attack?

To prevent man-in-the-middle attack, you can set up strong mutual authentication and create a secure communication channel between two systems. Ideally you can use PKI, Public Key Infrastructure with digital signatures to authenticate both sides and establish a trust relationship through a central Certificate Authority (CA), and using a protocol such as SSL or IPSec to create a tunnel. To made a man-in-the-middle attack happen, the attacker would need a valid certificate from a CA trusted by one of the victims, but they cannot get it.