CyberHunter
Local dataset, no network
// File transfer & sharing

Port 8912: Windows Client Backup

Port 8912 is assigned by IANA to wcbackup (Windows Client Backup).

8912

How wcbackup works

File transfer & sharing
client:89121/32/33/3wcbackup client:89121/32/33/3wcbackup

Files are sent over port 8912 in pieces and reassembled on the other side.

Transport
TCP · UDP
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
File transfer & sharing
01 Security

Is port 8912 dangerous?

We have no specific security note for port 8912. Its risk depends on the program actually listening on it. General advice for file transfer & sharing services:

  • Prefer encrypted protocols (SFTP, FTPS, SMB 3 with encryption).
  • Disable anonymous access and restrict shares or exports to known hosts.
  • Never publish file sharing protocols to the Internet.
02 Registry

IANA registry entries for port 8912

ServicePortTransportDescriptionReferenceUpdated
wcbackup 8912 TCP, UDP Windows Client Backup - 2005-11

// source: IANA service name and port number registry

03 Check it

Which program uses port 8912, and is it reachable?

Linux

sudo ss -ltnup 'sport = :8912'      # process listening on 8912
sudo lsof -nP -i :8912

macOS

sudo lsof -nP -i :8912

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 8912 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 8912
netstat -ano | findstr :8912

From another machine

nmap -p 8912 -sV <host>
sudo nmap -sU -p 8912 <host>
nc -zv <host> 8912

Block it in the firewall

sudo ufw deny 8912/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 8912" -Direction Inbound -LocalPort 8912 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 8912 used for?

Port 8912 is assigned by IANA to wcbackup (Windows Client Backup).

Is port 8912 TCP or UDP?

Port 8912 is registered for TCP and UDP.

Is it safe to open port 8912?

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. Prefer encrypted protocols (SFTP, FTPS, SMB 3 with encryption).

How do I check if port 8912 is open?

On Linux run "ss -ltnup 'sport = :8912'", on macOS "lsof -nP -i :8912", and on Windows "netstat -ano | findstr :8912" to see the local process. From another machine, "nmap -p 8912 <host>" shows whether it is reachable.

05 Related
:445 SMB tcp · udp · critical risk :21 FTP tcp · udp · sctp · high risk :139 NetBIOS Session tcp · udp · high risk :69 TFTP udp · tcp · high risk :2049 NFS tcp · udp · sctp · high risk :873 rsync tcp · udp · high risk :20 File Transfer [Default Data] tcp · udp · sctp :115 Simple File Transfer Protocol tcp · udp

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