What it is
Direct server-control access: SSH, RDP, Telnet, VNC, WinRM.
Why it is risky
Public exposure is the #1 target for brute-force and credential theft; Telnet and VNC are cleartext, making them worse.
What to do
Narrow with SSH keys · MFA · allow-listed IPs (or a VPN/bastion), and retire Telnet entirely.
Is it listening on your server?
Linux
ss -ltnp 'sport = :23'Track these versions on your own servers
InfraGuard collects installed software versions from every server and flags the ones with known vulnerabilities. Self-hosted — nothing leaves your network.