Internet TCP port 23 is primarily used by the Telnet protocol, which is a network protocol used on the Internet or local area networks to provide a bidirectional interactive text-oriented communication facility. It was widely used for remote device management, but due to security concerns, it has been largely replaced by SSH. Some examples of software that use this port include PuTTY and the native Telnet client included in many operating systems. However, its use is generally discouraged due to the lack of encryption for transmitted data.
TCP port 23, also known as the Telnet port, has been a common target for hackers due to its use for unencrypted communication. In the past, hackers have exploited this port to gain unauthorized access to systems by intercepting the unencrypted data, which often includes login credentials. For instance, the Mirai botnet, which caused widespread internet disruption in 2016, primarily targeted IoT devices with open Telnet ports. Similarly, the Bashlite malware also exploited TCP port 23 to infect hundreds of thousands of IoT devices. These examples highlight the vulnerability of TCP port 23 and the importance of securing it against potential exploits.
