“Set up Remote Desktop on an office computer, map the port to the public internet, and you can connect back from home to work” — many companies do this. It looks convenient, but it is a favorite entry point for ransomware and hackers. Today we will make it clear why you should not expose Remote Desktop (RDP/3389) directly to the public internet, how dangerous it really is, and how secure remote access should be done.
The Bottom Line First
Opening the Remote Desktop port (default 3389) directly to the public internet is like hanging a sign on your company’s front door telling every scanner in the world, “There is a door here — come try the password.” It is one of the most common entry points for ransomware and intrusions at small and medium-sized businesses. The right approach is not to “hide it by changing the port,” but to not expose it to the public internet at all, and instead use zero trust/VPN-style access that verifies identity first and then establishes an encrypted channel.
How Dangerous Is Exposing RDP to the Public Internet?
- Automated scanning across the internet, around the clock: huge numbers of automated programs scan for open port 3389 twenty-four hours a day. The moment you map it out, it will be found within minutes.
- Brute-force password attacks: once it is found, attackers begin continuously trying account names and passwords. Weak credentials are cracked within hours, and once they get in, they have full control of that machine.
- A primary entry point for ransomware: many ransomware incidents come in through compromised RDP — after entry, attackers encrypt the entire disk and then spread laterally to shared drives and other machines.
- Vulnerability risk: RDP itself has had serious vulnerabilities in the past (such as high-risk flaws that can spread like a worm). Exposing it to the public internet means that even a slightly delayed patch can leave you directly compromised.
A Few Common “Fake Security” Measures That Do Not Actually Work
| Measure | Why it does not work |
|---|---|
| Changing the port (3389 → something else) | Scanners sweep every port; changing the port only blocks the most rudimentary probes, not automated tools |
| Just setting a complex password | It stops brute-force attacks but not vulnerability exploits or credential leaks — and as long as it is exposed, it will be attacked continuously |
| Adding an IP allowlist | Employees’ external IPs change frequently, making maintenance difficult, and one loose configuration undoes the protection |
| Using certain personal remote-control tools | In enterprise settings, permissions are coarse, auditing is weak and compliance is difficult — unsuitable for formal production environments |
The Right Approach: Do Not Expose It — Verify Identity Before Connecting
The core principle of secure remote access is this: business systems (including Remote Desktop) are never directly exposed to the public internet; only identity-verified users can reach the authorized machine through an encrypted channel. There are two main ways to put this into practice:
- Zero trust remote access (recommended): trust nothing by default; every access request verifies identity and permissions, and business systems are “invisible” to the public internet (scanners cannot even find them). It provides per-account authorization, full auditability, and one-click revocation when an employee leaves.
- Traditional VPN: it can also close off the entry point, but “once you are on the VPN, you are on the whole internal network,” and permissions are coarse. It works as a transitional measure, but zero trust is the better long-term choice.
For small and medium-sized businesses, the most hassle-free option is a SaaS-based zero trust solution. Take sTrust as an example: its control plane is located in China and has completed ICP filing, and it works alongside MLPS 2.0 (China’s Multi-Level Protection Scheme). Employees install a client and, only after identity verification, can reach authorized internal resources (including Remote Desktop), with no port exposed to the public internet. It provides per-account authorization, one-click revocation when employees leave, and stable direct connections within China, and because it is software-based, no hardware purchase is needed. Beijing-based companies that want local implementation can also have Siwenlide bundle networking, security, and remote access into a single engagement.
Three Things You Can Do Right Now
- Audit first: confirm whether your company has mapped 3389 (or any other Remote Desktop/management port) to the public internet, and if so, shut it down as soon as possible.
- Change the channel: replace “direct public-internet connection to Remote Desktop” with “connect to zero trust/VPN first, then access Remote Desktop from inside the network.”
- Harden accounts: use strong passwords plus multi-factor authentication for critical accounts, and assign permissions on a least-privilege basis.
Frequently Asked Questions
Q: If I change the Remote Desktop port from 3389 to something else, am I safe?
A: No. Automated scanners sweep all ports, so changing the port only blocks the most basic probes, not professional automated attacks. The fundamental fix is to keep it off the public internet.
Q: I have set a very complex password — can I still be compromised?
A: A complex password stops brute-force attacks, but not protocol vulnerability exploits or credential leaks; and as long as the port is exposed, it will be attacked continuously. Security starts with reducing your exposure.
Q: Our employees really do need to connect to office computers from outside. What should we do?
A: Have them authenticate through zero trust/VPN first and establish an encrypted channel, then access Remote Desktop from inside the internal network. This enables remote work without opening the port to the public internet.
Q: We are an SME with no dedicated IT or security staff. How do we implement this?
A: Use a SaaS-based zero trust solution (such as sTrust) — software-based activation, no hardware purchase — or hand it to an IT Operations Services provider to configure and maintain it for you.
Still exposing Remote Desktop to the public internet? Switch to a secure connection method now
sTrust Zero Trust Remote Access: business systems stay invisible to the public internet, identity is verified before any connection is made, with per-account authorization, one-click revocation when employees leave, and support for MLPS 2.0 (China’s Multi-Level Protection Scheme) — software-based activation with no hardware purchase and stable direct connections within China. Visit strust.siwenlide.com for a free trial; Beijing-based companies wanting local implementation can call 400-686-2011 or visit siwenlide.com.
