← Port Encyclopedia
139

NetBIOS-SSN

TCP
Windows Critical Risk
NetBIOS Session Service — file sharing, printer sharing, EternalBlue (MS17-010)

🔍 How to Scan Port 139

nmap -sV -p 139 target
nmap -sV -sC --script=banner -p 139 target
nc -zv target 139

🛡️ Security Considerations

  • Scan port 139 with nmap -sV to identify the exact service and version
  • If NetBIOS-SSN is not needed, close or firewall this port immediately
  • Check for default credentials if a management interface runs on this port
  • Use searchsploit netbios-ssn to find known exploits
  • Monitor traffic on port 139 with Wireshark or tcpdump for anomalies
  • Ensure the service is patched to the latest version to prevent known CVE exploitation

🔗 Related Windows Ports

Port 135
MSRPC
Port 137
NetBIOS-NS
Port 138
NetBIOS-DGM
Port 445
SMB
Port 593
MS-DCOM
Port 5357
WSDAPI
Port 5985
WinRM-HTTP
Port 5986
WinRM-HTTPS
Port 35871
SMB-Alt
Port 47001
WinRM-Alt

📍 Nearby Ports

Port 134
Port-134
Port 135
MSRPC
Port 136
Port-136
Port 137
NetBIOS-NS
Port 138
NetBIOS-DGM
Port 140
Port-140
Port 141
Port-141
Port 142
Port-142
Port 143
IMAP
Port 144
Port-144
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