This chapter will focus on building a solid understanding of advanced network attacks. The topics covered will include defining what an man-in-the-middle (MITM) attack is, discussing characteristics of related attacks, and learning how to use MITM pen testing tools. Having awareness of how this type of attack operates will give the reader a significant advantage when defending against it. For example, detecting the early signs of an MITM attack is critical to prevent catastrophic damage from taking place. Without awareness, this attack can easily go undetected by network security teams. Many companies have been destroyed by this popular attack method. The repercussions of an MITM attack can have reverberating consequences, lasting years or even permanently. Reading this chapter will also provide an opportunity to gain applied knowledge and hands-on experience using an MITM tools.