Why Remote Desktop Connection Attracts Attackers
Any service that answers on the internet and accepts passwords becomes a target, and RDP endpoints are scanned relentlessly by automated systems that try billions of password guesses every day. Left unguarded, a host accepting remote desktop sessions will face dictionary attacks within hours of exposure. The good news is that the same protocol is also one of the most thoroughly hardened remote access technologies in existence — the difference between a target and a fortress is entirely in the configuration, and every step in this guide is free, built into Windows, and takes minutes.
The stakes are worth the effort: an attacker who wins an RDP session does not merely snoop — they hold a working login to your machine, with everything that implies. That is why professionals treat the configuration of Remote Desktop Connection as seriously as they treat antivirus and backups.
Layer One: Accounts, Passwords, and NLA
Begin with the fundamentals. Every account that can accept a remote session must have a long, unique password; password-guessing attacks fall first on short and reused credentials. Better still, limit exactly which accounts may connect: remove the Everyone entry from the "Remote Desktop Users" group and add only the people — or the one person — who genuinely needs access. An account that cannot connect cannot be brute-forced into a session.
Then enforce Network Level Authentication on the host. NLA requires the user to prove their identity before a full session is ever created, which blocks anonymous attackers from even reaching the Windows login screen and dramatically reduces both the attack surface and resource consumption of exposed endpoints. In System Settings, the toggle "Require devices to use Network Level Authentication" should never be switched off on a machine that accepts connections.
Account lockout policy completes this layer: configure Windows so that a handful of failed logons temporarily disables the account, turning an industrial-scale guessing campaign into a queue of locked doors.
Layer Two: Never Expose Port 3389 Directly
The single most dangerous configuration mistake is port-forwarding 3389 straight from a router to a host on the open internet — scanners find such endpoints in minutes. Instead, wrap the session in a tunnel. A VPN puts you inside the host's network first, after which the client connects as though local; the RDP port is never reachable from outside at all. For organizations, RD Gateway achieves the same result more elegantly: sessions traverse the internet inside a single HTTPS channel to a gateway server, which then brokers the connection to the real host, keeping the endpoint invisible to the outside world.
If VPNs and gateways feel heavyweight, a compromise exists: restrict the firewall rule for port 3389 to specific trusted IP addresses, so only known locations can even attempt a connection. It is not as robust as a tunnel, but it eliminates the vast majority of automated probing instantly.
Layer Three: Patching, Monitoring, and Session Hygiene
The RDP stack updates through Windows Update alongside the operating system, which is a quiet advantage of using a built-in client: keep the host patched and you keep the protocol patched. Old, unpatched Windows installs have historically hosted serious RDP vulnerabilities, so a machine that accepts sessions is a machine whose updates you must never defer for long.
Monitoring closes the loop. Event Viewer's security log records every failed and successful logon, and a surprising number of incidents are discovered by users who glance at those entries after something felt wrong. Review which accounts hold remote access occasionally, disable sessions for leavers immediately, and sign out rather than leaving sessions idle overnight — a forgotten open session on a public or semi-public network is an unlocked door in motion. When connecting from borrowed machines, use the client's /public behavior: never save credentials on a device you do not own.
A Checklist You Can Apply Today
In summary: unique long passwords for every remote-enabled account, membership of Remote Desktop Users trimmed to the minimum, Network Level Authentication enforced, account lockout enabled, port 3389 behind a VPN or gateway rather than the open internet, firewall rules restricted where possible, updates applied, and logons reviewed from time to time. Twenty minutes of work covers the checklist — and transforms the default client from a well-known attack surface into what it was designed to be: a rock-solid gateway to your own machines. For a look at how these layers fit into the tool as a whole, the security features described on our Remote Desktop Connection homepage make an excellent companion read.