Open ports enable services and applications to perform their functions properly. However, certain ports may pose security risks to your network. Read this article for a better understanding of why you should close risky, unused ports. Ports allow communication between devices. Internet-facing services and applications essentially listen on ports for a connection from the outside to do their jobs. Without ports, communication between hosts over the internet is not possible. At times, the problem with ports is that those that are not supposed to be open are inadvertently left exposed. An administrator at your company may have opened a port to satisfy a request and forgotten all about it. A firewall configuration may have been automatically modified by an application, leaving some ports open without your knowledge. It is often difficult to assess and mitigate risks associated with an open port at any given time. Unfortunately, open ports provide a pathway for attackers to exploit vulnerabilities in your system. Data breaches related to open ports happen all the time. At Intelligent Technical Solutions, this is an issue that we usually encounter from some of our clients. However, through an in-depth network assessment, we can discover open ports and services that potentially put our clients' networks at risk. We have been doing the same thing for our 368 clients and counting over the past 18 years. In this article, we explain what open ports are and the security implications of having them open. We also discuss how they work and what you can do to secure them. Before we discuss why leaving some ports open is a security risk, let's first look into the specifics of what ports are. The term port refers to a communication endpoint or where all network communications start and end. A port identifies a specific process or service and is assigned a number depending on its specialized purpose. In simpler terms, ports enable devices to tell what to do with the data they receive over a similar network connection. For instance, emails are routed through a different port (port 25) than websites (port 80). A port currently in use cannot run another service on it and will return an error message. The transport layer of the Internet Protocol Suite, such as the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP), uses ports to transmit and receive chunks of information, known as packets. An open port refers to a TCP or UDP port number that is actively accepting packets. In other words, behind it is a system that is receiving communication. A closed port, on the other hand, rejects or ignores packets. Some ports are reserved for specific protocols and are therefore required to be open. In addition, ports are opened depending on your firewall configuration or operating system: what is open on one may be closed on another. Open ports are not the issue per se. It's the applications and services listening on these ports. Attackers can easily exploit weaknesses in the applications listening on a port. Hackers can take advantage of security vulnerabilities in older, unpatched software, weak credentials, and misconfigured services to compromise a network. Some ports are not intended to be publicly exposed. For instance, the Server Message Block (SMB) protocol, which operates over TCP ports 139 and 445, is open by default in Windows machines. It is meant only for file sharing, printer sharing, and remote administration. Due to numerous vulnerabilities in the earlier versions of the SMB protocol, it was exploited by threat actors in the highly publicized WannaCry ransomware attack. Computers infected with WannaCry scanned its network for devices accepting traffic on SMB ports to connect to them and spread the malware. In addition, some ports are prone to abuse. An example is Microsoft's remote desktop protocol (RDP), which allows a user to access a remote host. According to ITS Director of Operations Peter Swarowski, there are many attack vectors for bad guys trying to get in through RDP. "Some of them are unpatched systems with known vulnerabilities where they can bypass all authentication and get right into whatever is hosting RDP right away. Some of it is brute force, so if you have RDP exposed and you don't have the means for locking out accounts from several failed logins, hackers can get in that way," he explained. Here's how you can secure your perimeter from the risks posed by vulnerable, unused, or commonly abused ports, according to Swarowski: If a business needed something like RDP, ITS would use an encrypted VPN connection to access RDP instead of leaving it open to the internet. Users need to connect to the VPN first before they can gain access to your RDP. That way, the VPN has to be attacked and bypassed first before the attackers can then get into a vulnerable RDP connection. Having multi-factor authentication (MFA) helps significantly in securing an open service. Even if you have a credential leak or a brute-force attempt, the threat actors would be challenged with an additional code or authentication method that they would not be able to bypass. Network segmentation is a process by which a larger network is divided into smaller parts or subnets. If you have an open DVR (Digital Video Recorder) port for your camera system, another option for securing that is segmenting it off the rest of your network. Even if somebody gets into this DVR, they can't get into your server and your workstations or go after more critical data. ITS runs a process that looks for unsafe open services, such as unencrypted, legacy ports on clients’ networks, so administrators can close them or replace them with a secure version. A weekly check is initiated on every port on every managed device to identify which ones are risky and need to be restricted. Your attack surface (i.e., the sum of all possible points that attackers can exploit) should be limited in size. Through a comprehensive network assessment, you can identify vulnerabilities in your physical and digital environments, including unused, exposed ports. Some open ports pose a danger to your system and should be secured. Keep your attack surface small with the help of ITS. ITS can assist you in ensuring the security of your infrastructure. Get in touch with our account representatives today for your free network assessment.What Are Open Ports and How Do They Work?
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What Makes Open Ports Dangerous?
How to Secure Open Ports
1. Access ports using a secure virtual private network (VPN).
2. Use multi-factor authentication.
3. Implement network segmentation.
4. Scan network ports regularly.
Manage Your Attack Surface
FAQs
Open Ports: What They Are and Why You Need to Secure Them? ›
Open ports are the building block of internet communication and in themselves are not a security risk. However, hackers can use vulnerable, unpatched, misconfigured, or infected underlying services in conjunction with open ports to move laterally across the network and gain access to sensitive data.
What are open ports and why you need to secure them? ›Open ports identify network endpoints that allow data exchange between devices. Ports facilitate various internet services and applications, allowing them to function properly. While open ports themselves do not threaten your network's security, they can be abused by hackers.
Why is it important to protect ports? ›Sometimes the goal is to protect the vessels themselves, as well as their passengers and cargo. For example, a port is a very busy place, and a potential criminal could try to take advantage of the chaos and steal some of the cargo off of a ship or plane.
What ports need to be opened? ›| Port | Protocol |
|---|---|
| 22 | TCP |
| 123 | UDP UDP is a part of the TCP/IP family of protocols used for data transfer. UDP is typically used for streaming media. UDP is a stateless protocol, which means it does not acknowledge that the packets being sent have been received. |
| 443 | TCP |
| 1645 | UDP |
Leave port 80 open for user convenience so that browsers that default to HTTP on port 80 can get properly redirected to HTTPS on port 443. Otherwise, they're going to get connectivity errors if either their browser doesn't default to HTTPS or at least check if HTTPS is available for them.
Why is it important to know what ports are open? ›Open port vulnerabilities pose a significant security risk to your organization. If left exposed, ports are a gateway for hackers to breach your network and steal your data.
What are the most secure ports? ›Port 443 is the default port for HTTPS data, the secure version of HTTP, Port 22 is used for Secure Shell data, the text-based console used primarily with Linux/Unix systems and network devices, Port 3389 is assigned for RDP (Remote Desktop Protocol), primarily used for accessing the console of Windows-based systems.
What is the need for port security? ›Prevents Thieves from Stealing Goods. Since shipping containers cannot be manned at all times, port security is essential for keeping goods safe from thieves. Some areas of ports are inaccessible for human patrol, but other security measures can protect these items from thieves.
What is the biggest threat to port security? ›Physical port security involves the risks to the perimeters of the port. Risks to port security involves natural risks such as hurricanes and flooding, man-made risks such as operator error, and weapon risks such as chemical, biological and nuclear material.
Why ports are very important? ›Ports serve as important transportation hubs that facilitate goods movement to businesses in local communities and worldwide markets. As illustrated in the figure at right, ports can connect goods to consumers through our highway system, railroads, air transit and domestic marine highways (water transportation routes).
What is the most common open port? ›
- HTTP – Port 80.
- HTTPS – 443.
- FTP – 21.
- FTPS / SSH – 22.
- POP3 – 110.
- POP3 SSL – 995.
- IMAP – 143.
- IMAP SSL – 993.
| Port | Protocol | Recommended Action |
|---|---|---|
| 139 | TCP and UDP | Disable always. |
| 445 | TCP and UDP | Disable always. |
| 161 | TCP and UDP | Disable always. |
| 389 | TCP and UDP | Disable always. |
Enter "telnet + IP address or hostname + port number" (e.g., telnet www.example.com 1723 or telnet 10.17. xxx. xxx 5000) to run the telnet command in Command Prompt and test the TCP port status. If the port is open, only a cursor will show.
Is port 80 open a vulnerability? ›Port 80 vulnerabilities include a lack of encryption, which makes it susceptible to eavesdropping and packet interception. In addition, the services and applications that run on it are open to attacks such as SQL injection, cross-site scripting (XSS), and cross-site request forgery.
Can I leave port 443 open? ›While port 443 is generally considered to be a secure port, opening it on your computer can increase your risk of being hacked. This is because attackers know that port 443 is often used for sensitive traffic, such as online banking and shopping.
Is port 443 TCP or UDP? ›If you need to send secure or encrypted information to the web server, you'll be using HTTPS, that's the hypertext transfer protocol secure protocol, and it uses TCP port 443 to have that encrypted channel to the web server.
What are the open ports designated for? ›In cybersecurity, the term open port refers to a TCP or UDP port number that is configured to accept packets. In contrast, a port that rejects connections or ignores all packets is a closed port. Ports are an integral part of the Internet's communication model.
What are the reasons for port security? ›- Firstly, it helps protect the network from unauthorized access and malicious attacks. ...
- In addition, port security also helps reduce the risk of security breaches and helps maintain the privacy and integrity of the network.
Ports allow computers to easily differentiate between different kinds of traffic: emails go to a different port than webpages, for instance, even though both reach a computer over the same Internet connection.
