Why is port 139 listening?
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 happens when port 139 opens?
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.
What is the problem with 139 port?
Firewalls, as a measure of safety always block this port first, if you have it opened. 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.
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”
How do I open TCP port 139?
Open firewall ports in Windows 10
- Navigate to Control Panel, System and Security and Windows Firewall.
- Select Advanced settings and highlight Inbound Rules in the left pane.
- Right click Inbound Rules and select New Rule.
- Add the port you need to open and click Next.
Is port 139 required for SMB?
As such, SMB requires network ports on a computer or server to enable communication to other systems. SMB uses either IP port 139 or 445.
Is port 139 needed for SMB?
SMB has always been a network file sharing protocol. As such, SMB requires network ports on a computer or server to enable communication to other systems. SMB uses either IP port 139 or 445.
How do I exploit port 139?
That being said by Mr Protocol, what he says is true, however, port 139, is usually used to identify Windows systems, so if you’re looking to exploit “port 139” as you put it, first thing you will want to do is identify a system with port 139 open, thoroughly determine if its a true open port, the OS, or if its a honeyport/honeypot.
What ports are open on port 139?
With port 139 open, most likely, you should see ports 135-139 open, and be able to fingerprint it as windows of some sort.
Why do I need to disable port 139 in TCP?
TCP Port 139 is one of the highest-risk ports on the network and you may need to disable the port 139 to avoid the WannaCry ransomware attack. If the computer supports both NBT protocol and the TCP/IP protocol, the NetBIOS session will start via the available 139 port or 445 port. Why do the rules drop outbound connections to ports 135 139 and 445?
What is the use of ports 135 139 and 445?
Ports 135, 139 and 445 are traditional Microsoft networking port. These can be used to propagate the Malware in a network. The attacks make use of the port 445 to exploit the system through LAN.