Port 23: Telnet
Open Telnet port detected on a publicly accessible host.
Severity: Critical | Port: 23
What is Telnet?
Telnet is a protocol from the 1960s that provides remote command-line access to a computer. It was the standard way to manage servers before SSH was invented. Telnet operates on port 23 and establishes an interactive text session with the remote host.
Why this is a problem
Telnet sends all data completely unencrypted — including passwords, commands, and output. Anyone on the network path between you and the server can capture everything. There is no modern justification for running Telnet on a publicly accessible server.
What you should do
- Disable Telnet immediately and close port 23
- Replace it with SSH (port 22), which provides the same remote access functionality with full encryption
- If Telnet is required for legacy equipment, isolate it behind a VPN so it is not reachable from the public internet