What Are The Most Common Types Of Network Vulnerabilities?

By Fortra's Digital Defense

Network vulnerabilities constantly evolve, resulting in the loss of valuable information and revenue from businesses. Though threat actors can find new weaknesses every day, some of their methods remain the same. Hackers have tried-and-true methods for infiltrating a seemingly secure network, and they employ various tricks, devices, and information to get the job done.

Small businesses often do not give their network systems adequate protections, either because their leaders do not incorporate strong security policies or do not fully understand how to guard their systems. Exploitable bugs and weaknesses are always present within networks, but understanding how hackers manipulate them gives businesses a clearer picture of what they must do to prevent authorized users from accessing any valuable digital asset.

Learn how to secure your network and find your vulnerabilities and security weaknesses.

Understanding Network Security Vulnerabilities

Network security vulnerabilities are weaknesses or flaws within the system’s software, hardware, or organizational processes. Network vulnerabilities can be either non-physical or physical.

  • Non-Physical: This weakness refers to anything related to data and software. Vulnerable operating systems that the IT department does not update will leave the entire system susceptible to threat actors. If a virus or malware downloads into the operating system, it could potentially infect the whole network.
  • Physical: Physical protection for networks includes actions like storing an on-site server in a rack closet and securing it with a lock or requiring a code to access a secure point of entry. Because servers store valuable information such as consumer data or trade secrets, they need tight, physical security controls like biometric scanners or access cards to reduce or eliminate the risk of unauthorized users accessing the area and equipment.

There are plenty of network vulnerabilities a hacker can exploit to access valuable information, but the four most common types are:

  • Malware: Malicious software includes worms, Trojans, and viruses that can infiltrate a device or host server. People unknowingly buy or download malware that will exploit a network vulnerability.
  • Outdated or Bugged Software: Systems running an application without adequate patching can potentially infect an entire network if someone finds and manipulates the flaw.
  • Social Engineering Attack: Network intruders can use various methods to fool workers into unintentionally giving up confidential data like passwords or login information.
  • Misconfigured Firewalls or Operating Systems: Default settings are easy to guess and are well known.

Without adequate web security measures, the network becomes susceptible to devastating cyber attacks like distributed denial of service attacks that bring down database servers or restrict authorized user access to block out workers and IT management teams.

Learn how Fortra VM can find your network vulnerabilities.

Common Network Vulnerability Issues

Network security vulnerabilities involve three broad categories:

  • Hardware
  • Software
  • People

Hardware Issues

Every device within the network can be problematic for a business unless the IT department is aware of them and maintains each one with the most recent firmware upgrades available to patch flaws. Routers are an example of hardware equipment. If the IT department chooses not to use firmware to upgrade the device or if no patches are available to fix a known weakness, they must replace it with the latest model with up-to-date patches.

Physical Device Security

The easiest way for an intruder to infiltrate a network is by using a device containing a virus or malware directly on a machine already connected to the system. They can install the malware quickly into the equipment using USB drives or download codes. The malicious application will either install spyware or a backdoor code that could capture vital information that would provide access to more sensitive data, like keystrokes or the option to view network traffic.

Hackers don’t need to be physically present on the premises to access network devices. One tactic they use is mailing USB devices with malware to unsuspecting workers who unwittingly infect their workstation, and possibly the network, as soon as they insert it into the USB port.

Firewall Issues

Firewalls are a must-have measure for all businesses with web networks, whether they are part of a router, separate box, or virtual device. The firewall prevents unauthorized access and blocks blacklisted IP addresses from open ports. Sometimes firewalls upload unnecessary or unwanted services into the network as part of its program.

Unless the IT department is aware of the services and keeps them updated or removes them altogether, the firewall will have an exploitable vulnerability.

Another benefit of using firewalls is its ability to block cross-site scripting and SQL injection attempts. SQL injection is a hacking technique that interferes with application queries to view sensitive data. Having multiple firewalls is necessary for segmenting a network containing confidential information beyond the edge of the network, which is more accessible to anyone attempting to hack the system from the outside.

Wireless Access

Wi-Fi is a convenience that many businesses use, but it poses a severe vulnerability because it immediately gives users access beyond the firewalls. If it is not password protected, it is accessible to anyone, including intruders looking for ways into networks. With wireless access points, network security is at risk because all devices with an internet connection can read traffic flowing in and out of the network.

When a company provides a standard password for wireless service to give everyone access, it defeats the purpose of having a password. Intruders can use this information as an entry point into the company’s private networks by imitating the network’s Wi-Fi and sending employees to fake access points.

Strong passwords that are not readily available to everyone, especially to the public, are among the best security tools against these types of threats.

IoT Devices

As of 2020, there are an estimated 20.4 billion devices connected to the IoT, the "internet of things." The term refers to a collection of objects like thermostats, light bulbs, and locks that can compute and analyze data. They have sensors or software that allow them to connect to a system, network, or device and transmit data over the internet.

Despite the convenience of such objects, some are cheaply made and offer minimal protection against cyber attacks. They are also almost impossible to update with firmware, leaving them vulnerable.

If a business has IoT devices, IT professionals should only buy them from reputable vendors and connect them to a separate subnet to reduce the risk of attack to the primary network.

Unauthorized Devices

Unauthorized devices are serious security issues, and there are several ways they can be problematic to an internal network.

USB thumb drives are notorious for transmitting malicious applications or storing valuable data because they are small, portable, and have broad storage capabilities. Despite their versatility, USB drives are often not considered threats, but they are problematic if they have endpoints that can read and execute data. Examples of these devices include:

  • MP3 players
  • Fax machines
  • Printers
  • Digital cameras

Laptops and smartphones also pose threats to the operating system. They are discreet, they have their own complete operating system, and they have Wi-Fi network connections. A laptop or netbook can also use its ethernet port to connect directly to the system.

These devices can run malware and exploit application vulnerabilities with ease, whether they belong to a visiting intruder or a daily employee. Modern laptops and smartphones have ample storage capabilities to store sensitive information.

Recordable media, like CDs, work the same way. They can transmit and store data.

Security policy governing what devices are allowable in the work environment is one effective way for an IT department to deal with unauthorized devices. In addition to restricting access points, the security team should ensure that files on work laptops and thumb drives have encryptions to protect valuable data. Finally, no computer should retain VPN or Wi-Fi access because these are too exploitable.

Software Security Vulnerabilities

Regardless of a network’s sophistication level, it uses software capable of running various operating systems and applications. If any of that software contains an exploitable flaw, it’s only a matter of time before a hacker finds it and infiltrates the network. IT professionals within the organization must be aware of every software application to implement effective patch management.

Outdated and Buggy Software

Outdated software continues to be the root of network vulnerability and subjects your business to a greater chance of a network attack. To circumvent this problem, the security team must install software updates as soon as they are available. The business should also perform a vulnerability scan and conduct penetration testing to ensure network security is up to date.

Security experts will use vulnerability scanning to detect flaws that an unauthorized user could manipulate. With penetration testing, a third party will attempt to manually exploit the system’s weaknesses using the same methods as a threat actor.

Security measures must also be in place for software the business no longer uses. Content management systems often include plug-ins and add-ons from the internet. These additions can be affected over the internet, so either keep them updated or remove them entirely from the system.

Unmanaged Software

Sometimes employees will download software they bring into the workplace without receiving approval from the IT department. This action is risky because there is no way for the company’s network security team to vet or manage it. It’s also possible that the software contains a Trojan horse with a virus or malware that could lead to network vulnerabilities.

Unmanaged software is usually the result of employees who want to make their jobs easier while circumventing the IT department’s strict rules. Instead of allowing employees to be a potential security risk to the business, the IT team should partner with workers and remind them of the security policies regarding unauthorized software use.

Security Vulnerabilities from Configuration

Configurations, or a lack thereof, also contribute to software security vulnerabilities that could lead to unauthorized access and cause a security breach. Web applications include default settings, including passwords, designed to make the application setup easier for the user without regard for web security.

Because these default settings are widely known and easily guessed, security professionals should not use them after the initial setup. Remember to change the names of admin accounts and create robust passwords to restrict access. Virtual Private Networks (VPNs) are accessible everywhere to employees, but if they’re a part of your business, they must have the correct configurations to reduce security risks and attacks.

User Issues

Despite all efforts to protect computer systems, they require people to manage them, and people often make mistakes. Whether they use weak passwords, fall for a phone scam, or don’t fully understand a security policy, employees can be a security risk to their workplace.

Authentication and Authorization

People tend to lean on weak passwords both inside and outside of work because they are easy to remember. Unfortunately, that means they are also easy to guess or hack. Even if the software on computer networks has specific requirements for users to create passwords, it’s not enough protection against a savvy threat actor.

For superior cyber security, use password generators to produce a unique user code consisting of upper- and lowercase letters, numbers, and special characters. The purpose of these passwords is that they are hard to decipher. Secure password managers can help workers keep track of any unique code if they cannot commit it to memory.

It also helps to include multi-factor authorization in your web security. The threat of password theft drops significantly by requiring a second form of approval via text message, a special device, or a mobile application.

Deception of Users

People often fall for trickery through scam phone calls, phishing e-mails, and fake websites to gain access to sensitive information within the system.

E-mail is a common way for intruders to glean information. Companies use this service to send information among clients and colleagues, but an e-mail can easily be resent to an external party or carry a malicious web application to phish for data they can use elsewhere, like leadership names and passwords. All e-mails that contain valuable information must be to verifiable recipients and senders.

Employees do not have to be disgruntled to become a network vulnerability. They can risk network security by accidentally accessing a file system without approval, reading confidential information on their monitor without being aware of who is watching, and not verifying intruders in disguise.

Security awareness training with accompanying policies can educate employees and prevent some damage. The IT department should also increase information security by restricting employee access and only allow users the data they require to complete their job efficiently.

How To Find Network Vulnerabilities

Finding network vulnerabilities requires the right vulnerability scanning tools. These tools include the ability to locate and identify network devices, open ports, and software within that network. The vulnerability scanner collects this data from the system and identifies these items. Then, the scanner is able to assess this data and compare vulnerabilities to the known database.

The right network vulnerability scanning tool shouldn’t be a drain on resources, it shouldn’t be overpowering with its scans, and it shouldn’t affect the network’s stability or bandwidth.

A scanner should also know when new connections and new devices are added to the network. New vulnerabilities can show up with new hardware, new programs, and new devices added to the network. The right scanner should automatically scan whenever something new is connected.


Protecting network vulnerabilities is complicated but not impossible. Every device, person, and software within the business is a potential risk to web security unless updated protections, procedures, and security policies are in place. Everything from unique password creation for accessing computer system restrictions to device vetting will offer significant protection for your business’s network when used together.

Give your company the cyber security it deserves with the help of Digital Defense, a leading provider of security assessment solutions. For more than 20 years, our team of network security experts has been a driving force in reducing cyber threats.

About the Author

Our Vulnerability Research Team consists of credentialed (Security+, Network+, CISSP) cybersecurity experts with decades of combined experience in research, analysis, and the discovery of unknown vulnerabilities. 

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