Here, we’ll discuss a few port scanning strategies and even quickly teach you how to close vulnerable ports. So, let’s get started.
What Are Some Main Port-Scanning Techniques?
A port scanner checks for one of the four potential statuses—open, closed, filtered, or unfiltered. The filtered means that a firewall or filter is blocking the port, whereas unfiltered indicates that—despite the port being accessible—the scanner cannot determine if it’s open or closed.
Some port-scanning techniques require completing the transmission communication protocol (TCP) handshake that creates the connection to transfer data between two devices. The TCP half-open port scan can check thousands per second, making it one of the fastest methods. Half-open port scanning does not require completing the handshake. On the other hand, TCP connect port scans do finish the handshake, making them a slower option.
You can also do a ping scan. It checks for a single live target or can sweep an entire network block. However, there’s usually no need for everyday computer users to know the differences between common port-scanning strategies. That’s because convenient tools make finding and fixing vulnerabilities easier without network security backgrounds.
How to Know if a Port Is Vulnerable and Close It
Computers need ports to communicate with other machines on a network. The potential vulnerabilities rise with the number of open ports. However, not all of them are at risk.
The following characteristics increase the chance of vulnerabilities, however:
An unpatched service used on the port Misconfigurations Poor network security rules
There are 65,536 ports and protocols available for computers to use. However, it’s probably comforting that a 2019 study by Alert Logic found that 65 percent of cyberattacks associated with ports focus on just three of them. Reducing your number of open ports minimizes your overall attack surface. However, you must understand how those ports work at a system level and which services and applications use them before making an overall decision about vulnerability.
Start by downloading one of the many free port-scanning tools and getting it to work. If you find open ports and want to close them, one option is to download a tool to make it easier.
For example, there’s a Mac app called Port Manager. It lets you find, open, close, and free up ports. Windows also has a command-line tool called Network Statistics, or netstat. It allows for finding and monitoring open ports.
While Windows settings and the Control Panel are useful for troubleshooting if your USB port stops working, you can also go into them to open, close, and create rules for ports.
What Can You Learn From Port Scanning?
A port scanner helps detect a possible security breach because it shows all hosts connected to a network and the associated services running on them. Many well-known companies deploy port scanning to detect visitors using remote access programs to carry out fraud. TD Bank, Chick-fil-A, and Ticketmaster are some brands believed to use port-scanning tools at certain stages of a visitor’s site usage.
A helpful way to think of it is that the services and technologies linked to a specific port may have security issues due to infrastructure flaws. That’s why penetration testers look for insecure ports when performing network reconnaissance.
Scans can highlight instances of sensitive data transferred over an insecure port. Getting that information can motivate you to look for secure alternatives, such as using HTTPS, SFTP, or SSH, before a cyberattack happens.
Port Scanning Is a Smart Preventive Measure
Using port-scanning strategies by downloading a free tool can help you enjoy more robust cybersecurity. However, remember that an open port alone is not necessarily a security vulnerability. It’ll be easier to spot potential cyber threats as you become more familiar with your network and its associated configurations.
