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// Directory & authentication

Port 7847: A product key authentication protocol made by CSO

Port 7847 is assigned by IANA to csoauth (A product key authentication protocol made by CSO).

7847

How csoauth works

Directory & authentication
userdirectorycsoauthresponse userdirectorycsoauthresponse

The client proves who it is on port 7847 and gets an answer (or a ticket) it can use with other services.

Transport
TCP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned1 registered service
Range
Registered (1024-49151)
Category
Directory & authentication
01 Security

Is port 7847 dangerous?

We have no specific security note for port 7847. Its risk depends on the program actually listening on it. General advice for directory & authentication services:

  • Keep directory and authentication services on internal networks.
  • Require signing or TLS and disable anonymous queries.
  • Monitor authentication failures for spraying and brute force.
02 Registry

IANA registry entries for port 7847

ServicePortTransportDescriptionReferenceUpdated
csoauth 7847 TCP A product key authentication protocol made by CSO - 2013-09-04
-7847-Reserved--

// source: IANA service name and port number registry

03 Check it

Which program uses port 7847, and is it reachable?

Linux

sudo ss -ltnup 'sport = :7847'      # process listening on 7847
sudo lsof -nP -i :7847

macOS

sudo lsof -nP -i :7847

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 7847 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 7847
netstat -ano | findstr :7847

From another machine

nmap -p 7847 -sV <host>
nc -zv <host> 7847

Block it in the firewall

sudo ufw deny 7847/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 7847" -Direction Inbound -LocalPort 7847 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 7847 used for?

Port 7847 is assigned by IANA to csoauth (A product key authentication protocol made by CSO).

Is port 7847 TCP or UDP?

Port 7847 is registered for TCP.

Is it safe to open port 7847?

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. Keep directory and authentication services on internal networks.

How do I check if port 7847 is open?

On Linux run "ss -ltnup 'sport = :7847'", on macOS "lsof -nP -i :7847", and on Windows "netstat -ano | findstr :7847" to see the local process. From another machine, "nmap -p 7847 <host>" shows whether it is reachable.

05 Related
:389 LDAP tcp · udp · high risk :636 LDAPS tcp · udp · moderate risk :88 Kerberos tcp · udp · high risk :3268 Global Catalog (LDAP) tcp · udp · high risk :1812 RADIUS udp · tcp · moderate risk :31 MSG Authentication tcp · udp :49 Login Host Protocol (TACACS) tcp · udp :56 XNS Authentication tcp · udp

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