What is port 139 NetBIOS SSN?
What is port 139 NetBIOS SSN?
Port 139 is utilized by NetBIOS Session service. Enabling NetBIOS services provide access to shared resources like files and printers not only to your network computers but also to anyone across the internet. Therefore it is advisable to block port 139 in the Firewall.
What is NetBIOS SSN used for?
| Name: | netbios-ssn |
|---|---|
| Purpose: | NETBIOS Session Service |
| Description: | TCP NetBIOS connections are made over this port, usually with Windows machines but also with any other system running Samba (SMB). These TCP connections form “NetBIOS sessions” to support connection oriented file sharing activities. |
| Related Ports: | 137, 138, 445 |
Is port 139 still used?
Port 139 is used for File and Printer Sharing but happens to be the single most dangerous Port on the Internet. This is so because it leaves the hard disk of a user exposed to hackers.
What service uses port 139?
SMB
Port 139 is used by SMB dialects that communicate over NetBIOS. It’s a transport layer protocol designed to use in Windows operating systems over a network. Port 445 is used by newer versions of SMB (after Windows 2000) on top of a TCP stack, allowing SMB to communicate over the Internet.
Is port 139 required?
If you are on Windows-based network that is running NetBios, it is perfectly normal to have port 139 open in order to facilitate that protocol. If you are not on a network using NetBios, there is no reason to have that port open. E-mail servers need ports 25 and 110 for SMTP and POP, respectively.
How do I block port 139?
To close port 139 (netbios-nbsession):
- Click on “Start” → “Settings” → “Control Panel”
- Double click on “Network”
- Select the “Configuration” tab.
- Scroll down network component list and find and select item starting with “TCP/IP -> …”
- Then select “Properties”
- Select the “Bindings” tab.
- Deselect each option then click “Ok”
Does smb2 use port 139?
SMB uses either IP port 139 or 445. Port 139: SMB originally ran on top of NetBIOS using port 139. NetBIOS is an older transport layer that allows Windows computers to talk to each other on the same network.
Is NetBIOS a security risk?
Vulnerabilities in Windows Host NetBIOS to Information Retrieval is a Low risk vulnerability that is also high frequency and high visibility. This is the most severe combination of security factors that exists and it is extremely important to find it on your network and fix it as soon as possible.
Does SMB2 use port 139?
Why is port 139 open?
The port is currently ‘listening. If you are on Windows-based network that is running NetBios, it is perfectly normal to have port 139 open in order to facilitate that protocol. If you are not on a network using NetBios, there is no reason to have that port open.
Why would the network security team be concerned about port 139 being open on a system?
Ports 135-139 range is associated with the SMB and NetBios this indicates that null sessions (no username or password) are allowed. Also, the concern with the ports being open would be when the service is DISabled because if the service is enabled then the ports should be open for the systems to use the service.
What is the use of port 139 in NetBIOS?
Session service (NetBIOS-SSN) for connection-oriented communication via port 139. Port 135: it is used for Microsoft Remote Procedure Call between client and server to listen to the query of the client.
What is port 139 in a firewall?
Port 139 is utilized by NetBIOS Session service. Enabling NetBIOS services provide access to shared resources like files and printers not only to your network computers but also to anyone across the internet. Therefore it is advisable to block port 139 in the Firewall.
What is NetBIOS and why is it dangerous?
NetBIOS is a protocol used for File and Print Sharing under all current versions of Windows. While this in itself is not a problem, the way that the protocol is implemented can be. There are a number of vulnerabilities associated with leaving this port open.
How to block ports 135 and 139 in Linux?
Because port series from 135 to 139 are most vulnerable therefore administrator can block either whole series or a specific port. Select Inbound Rules and click on New Rule. The select radio button for the port which will create a new rule that controls connections for a TCP or UDP port.
