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Port 3389Microsoft RDP

Remote Desktop Protocol (RDP) is a proprietary protocol developed by Microsoft to provide a graphical interface for remotely connecting to another computer or server. Commonly used by system administrators and remote users, RDP allows full control over Windows systems across networks, enabling maintenance, troubleshooting, or remote work capabilities. Despite being a widely deployed remote access solution, RDP can expose systems to significant security risks if incorrectly configured..

inRemote AccessNetwork ServicesSystem
transport
tcp · udp

2 transports registered

in transit
cleartext

payload readable on path

assignment
official

registered with iana

risk
4/10

caution

lookups
16,276

rank 182 of 993 · top 18%

Technical Details

what runs on :3389

Remote Desktop Protocol (RDP) primarily facilitates remote connections between client devices and Windows servers or desktops. It transmits screen images, keystrokes, and mouse movements between the remote host and client. RDP operates on port 3389, supporting both TCP and UDP transport layers, improving performance by reducing latency during multimedia streaming and input/output processes.

RDP encapsulates a suite of advanced features such as session shadowing, printer and clipboard redirection, audio redirection, and resource sharing, making it a robust solution for virtual desktop infrastructure (VDI), remote administration, and end-user support. It leverages components like the T.120 protocol for application sharing and employs a client-server architecture to facilitate seamless interaction.

Although primarily associated with Windows environments, various clients exist for Linux, macOS, iOS, and Android devices to interact with RDP servers. The protocol’s versatility ensures compatibility across diverse network setups, including local area networks (LANs) and wide area networks (WANs), supporting encryption and smart card authentication when correctly configured.

Security Information

exposure of :3389

risk score

4/ 10caution

worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.

remote access averages 4.0 across 110 ports — this one sits level with it.

in transit

cleartext

credentials and payloads are readable by anyone on path

assignment

official

registered with iana for this service — scanners fingerprint it by number

reachable over

tcp · udp

udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite

security overview

Common Vulnerabilities:

  • Weak authentication mechanisms, especially if relying solely on passwords
  • Susceptibility to brute-force password attacks
  • Exposure to exploits such as BlueKeep (CVE-2019-0708), enabling unauthenticated remote code execution
  • Man-in-the-middle attacks when encryption is weak or misconfigured
  • Lack of network-level authentication (NLA) allowing pre-authentication exploitation

Common Mitigations:

  • Enforce strong, multi-factor authentication and complex password policies
  • Enable Network Level Authentication (NLA) to reduce exposure prior to login prompts
  • Regularly patch RDP services and underlying Windows OS to remediate known vulnerabilities
  • Restrict access to port 3389 with firewalls, VPNs, and access control lists (ACLs)
  • Monitor and limit login attempts to detect and block brute-force activity
  • Use encryption protocols such as TLS to secure session data
  • Consider tunneling RDP over secure channels like SSH or VPNs and disabling direct public internet exposure whenever possible

Related Ports

all 110 in remote access →

the 8 most looked-up other ports in remote access — 110 ports carry that label.

portservicerisk
:8000Intel Remote Desktop / Alternate HTTP Portsafe
:8888D2GS Admin Consolecaution
:8881Atlasz Secure Servercaution
:5938TeamViewercaution
:8291Winbox MikroTik Admincaution
:8008IBM HTTP Server Admincaution
:135Microsoft EPMAPcaution
:23Telnetcaution

risk mix of the 8 listed

  • safe13%
  • caution88%

0 of 8 encrypted