Exploring password-based attacks

While performing a penetration test on a network, you will encounter systems that have remote access protocols and services running, such as Secure Shell (SSH) and even Remote Desktop Protocol (RDP). However, most IT professionals usually secure systems that have some type of remote access to prevent threat actors and unauthorized people from accessing and controlling those systems and devices. Many years ago, when I was breaking into the industry, I encountered an organization that was a victim of a cyberattack that affected their Voice over IP (VoIP) systems. Attackers redirected large volumes of international calls through the compromised company's VoIP systems, which resulted in large toll charges on their bills and reputational issues. This attack is usually referred to as Toll Fraud.

Being curious at the time, I suspected the attack occurred through the network, which led me to look at the configurations of the networking devices. One...