CyberHunter
LinkedIn profile - Bastien Cordier Email: contact@bastiencordier.pro
// Other services

Port 428: OCS_CMU

Port 428 is assigned by IANA to ocs_cmu (OCS_CMU), ocs-cmu (OCS_CMU IANA assigned this well-formed service name as a replacement for "ocs_cmu".).

428

How ocs_cmu works

Other services
client:428ocs_cmuresponse client:428ocs_cmuresponse

The client sends a request to port 428 and the ocs_cmu service answers.

Transport
TCP · UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned2 registered services
Range
Well-known (0-1023)
Category
Other services
01 Security

Is port 428 dangerous?

We have no specific security note for port 428. Its risk depends on the program actually listening on it. General advice for other services services:

  • Close the port if nothing on the host needs it.
  • Identify the process that listens on it (commands below) before opening it in a firewall.
  • Expose a service only to the networks that use it.
02 Registry

IANA registry entries for port 428

ServicePortTransportDescriptionReferenceUpdated
ocs_cmu 428 TCP, UDP OCS_CMU - -
ocs-cmu 428 TCP, UDP OCS_CMU IANA assigned this well-formed service name as a replacement for "ocs_cmu". - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 428, and is it reachable?

Linux

sudo ss -ltnup 'sport = :428'      # process listening on 428
sudo lsof -nP -i :428

macOS

sudo lsof -nP -i :428

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 428 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 428
netstat -ano | findstr :428

From another machine

nmap -p 428 -sV <host>
sudo nmap -sU -p 428 <host>
nc -zv <host> 428

Block it in the firewall

sudo ufw deny 428/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 428" -Direction Inbound -LocalPort 428 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 428 used for?

Port 428 is assigned by IANA to ocs_cmu (OCS_CMU), ocs-cmu (OCS_CMU IANA assigned this well-formed service name as a replacement for "ocs_cmu".).

Is port 428 TCP or UDP?

Port 428 is registered for TCP and UDP.

Is it safe to open port 428?

It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Close the port if nothing on the host needs it.

How do I check if port 428 is open?

On Linux run "ss -ltnup 'sport = :428'", on macOS "lsof -nP -i :428", and on Windows "netstat -ano | findstr :428" to see the local process. From another machine, "nmap -p 428 <host>" shows whether it is reachable.

05 Related
:4444 Metasploit default / krb524 tcp · udp · high risk :31337 Back Orifice / elite tcp · udp · high risk :1 TCP Port Service Multiplexer tcp · udp :5 Remote Job Entry tcp · udp :9 Discard tcp · udp · sctp · dccp :11 Active Users tcp · udp :17 Quote of the Day tcp · udp :18 Message Send Protocol (historic) tcp · udp

Latest vulnerability news

All news