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What is the Most Common Cause of Firewall Failure?

A firewall is a vital component of network architecture, and it is simply impossible to establish an effective cybersecurity defense without one. A firewall, however, does not end with installation; it must be supplemented with dedicated firewall policies and processes that are controlled and managed by an expert. Without this extra step, your firewall is very likely to fail, exposing your network to hackers, viruses, and other harmful traffic.

However, there will be times when the firewall fails to function properly, putting your customers' data and your company's IT infrastructure at risk. In this article, we look at what causes the most of firewall failures, from functional issues to configuration and compatibility issues.

1. Misconfigured

Firewalls are an important aspect of network security, and a misconfigured firewall can harm your organization and provide an attacker with simple access. Nonetheless, misconfigurations are all too typical.

According to Gartner's research, misconfiguration, not flaws, causes 95 percent of all firewall breaches. This signifies that a firewall's specs are inaccurate due to user error or a lack of investigation. In fact, Gartner estimated in 2016 that this ratio will grow to 99 percent by 2020.

Configuring a firewall necessitates meticulous preparation and a precise procedure - only an expert would know where to begin. However, all too often, the person in charge of firewall configuration fails to choose the right access control settings from the access control list.

Human mistake is frequently to blame for misconfigurations. Even if a user configures a firewall exactly as directed, it may still fail. For example, if a systems audit is not performed to discover specific holes or cyber risks, your company may unintentionally ignore a substantial risk and disregard a certain firewall configuration. An audit may also reveal the requirement for custom architecture rather than a set-it-and-forget-it approach.

Misconfigured firewalls might result in three serious consequences for your clients:

  • In order for a business to comply with PCI standards or regulations in retail, banking, or healthcare, it must have a properly set firewall. Fines are imposed for noncompliance.
  • Breach paths: A misconfigured firewall that allows unauthorized access can lead to data breaches, data loss, and stolen or ransomed IP.
  • Unplanned outages: A misconfiguration may prevent a customer from engaging with a firm, resulting in lost income. Large e-commerce companies, for example, could lose thousands or even millions of dollars until the error is addressed.

2. Software Vulnerabilities

While vulnerabilities caused by incorrectly configured network devices can cause havoc, firmware vulnerabilities represent a greater risk. There are flaws in any software program that attackers can exploit; this is true for firewall applications as well as any other piece of software.

Statistics show that firewall vulnerability is getting spread as much as other vulnerabilities.

Vulnerability distribution according to software type

Figure 1. Vulnerability distribution according to software type

The number of vulnerabilities increasing year by year as shown in stats.

Firewall Software Vulnerability distribution among years.

Figure 2. Firewall Software Vulnerability distribution among years

Assume a major firewall device vendor has disclosed a firmware vulnerability. The vendor needs time to deploy upgrades or patches. Your team is probably incredibly busy, and it's easy to fall behind on keeping firewalls up to date. Poor patching routines, on the other hand, can expose your organization to unnecessary firewall threats.

Worse, exploit codes for vulnerabilities are also made public on the internet. Bad actors make some of them available for free, while others charge thousands of dollars. Regardless of how much this costs, the threat they pose to businesses is enormous.

3. Hardware bottlenecks

Every modern business expert has faced this problem at least once. During a busy day or season, the firm network appears to be lagging at extremely slow rates. Workmates become irritated, vital activities are put on hold, and employee morale plummets to an all-time low. Worse, no one seems to be able to pinpoint what is causing the network slowdown.

Your hardware may cause issues with the firewall. There may be occasions when the load on the firewall grows significantly. As a result, if your hardware cannot keep up with the load, applications will begin to run slowly and network performance will suffer. To avoid similar problems in your company, you should invest in higher-capacity gear. However, because that is an expensive alternative, a more cost-effective approach is to disable some firewall functionalities. However, keep in mind that you should only disable functions that have no substantial impact on the firewall's operation.

4. Missing Firewall Policy

A secure network is essential for any business. To secure a network, a network administrator must develop a security policy that specifies all network resources within a company and the level of security required for those resources. Each policy is uniquely recognized by its name and applies security rules to transit traffic inside a context (source zone and destination zone). The traffic is categorized by matching source and destination zones, source and destination addresses, and the service (application) carried in the protocol headers of the traffic with the policy database on the data plane.

Firewall policy is missing or incorrect - This describes how a firewall handles inbound and outbound network traffic based on information security policies. A policy could have been badly written or simply not exist. As a result, the firewall fails.

How to Fix Problems with the Firewall?

We can divide issues into two-part Connectivity and Performance.

  1. Solving Connectivity Issues: You can troubleshoot connectivity issues by using the listed tools.
    • Netstat: On many Windows systems, the netstat tool can be used to troubleshoot connectivity difficulties by detecting whether an application is actually listening to the IP address you expect it to be on. Because Netstat is so versatile, there are more commands than can be listed here, but offers a comprehensive overview on their website. Technically, this program is integrated into Linux computers as well, but it is deprecated because it has been superseded by ss, which is a component of iproute2.
    • Iproute2: iproute2, the Linux kernel's successor to netstat, is a suite of programs for controlling TCP and inbound UDP IP networking and traffic control. Iproute2 includes several tools, including ip, ss, bridge, ip, rtacct, rtmon, tc, ctstat, lnstat, nstat, routef, routel, rtstat, and arpd. The most significant difference between iproute2 and netstat is the streamlined syntax for numerous commands. It also offers policy-based routing and network namespace support.
  1. Firewall Performance Issues: Because firewalls frequently contain networking hardware that is slower than the internet pipes to which they are connected, incorporating a firewall into your network architecture might result in major bottlenecks when traffic spikes occur. Faster hardware can theoretically assist to solve this, but because firewalls must buffer traffic and filter packets, there will always be increased latency when employing additional hardware. Fortunately, the suggestions below will assist you in overcoming frequent performance bottlenecks.
    • Streamline Network Traffic: One of the simplest methods to lessen the burden on your firewalls is to ensure that outgoing traffic adheres to your company's regulations. To put this protection in place, have your server managers identify internal servers that are sending out incorrect requests. Then have them change the systems to prevent that type of traffic.
    • Handling Incoming Requests: You can lessen the load on your firewalls by filtering undesirable traffic at the router level for incoming traffic. This can be accomplished by first recognizing inbound dropped requests that match your desired rules and then routing them as Standard Access Control List (ACL) filters. Although this process might be time-consuming at times, it is one of the most effective methods of improving network performance.
    • Simplifying Firewall Rules: Reducing the complexity of your firewall rules is considered a best practice for firewall configuration and one of the simplest methods to increase its performance. As part of routine housekeeping, you should also remove unused rules and objects. You can substantially simplify firewall rule maintenance and complexity by using firewall management tools, making it a viable task.

How to Test a Firewall?

Firewall testing ensures that the hardware/software firewall is functioning properly. Your machine may have thousands of ports open while connected to the Internet. If these ports are open, fraudsters may attempt to install a bot on your machine, transforming it into a zombie or part of a botnet.

There are numerous online firewall test sites, but you must be cautious about which one you respond to. Do not place all of your trust on a testing site provided by a company that wants to sell you a hardware firewall](/docs/network-security-tutorials/what-is-hardware-firewall). Firewall testing is required once your firewall has gone live to ensure that it is serving its purpose and that you have set it appropriately.

Firewall testing ensures that your firewall is protecting your network. Firewall testing tools might be proprietary or brand-specific. These tools are provided by vendors, thus users must speak with the firewall provider if they require them. These proprietary tools' firewall testing checklists focus on efficacy and look at specific parameters such as antimalware, application identification, and intrusion prevention. Firewall penetration testing utilities, on the other hand, are available for free online. Here are a few examples.

  1. Nessus

  2. Nmap

  3. Netcat

  4. Wireshark

There are other free firewall testing websites available on the Internet as well. The majority of these open-source alternatives evaluate performance while connected to the Internet and do not require software installation.

  1. Audit My PC Security (

  2. ShieldsUP (Gibson Research website

What Happens If Firewall Issues Are Not Resolved?

A firewall is just as important for security as an anti-virus tool. Firewalls prevent malware from propagating across a network and protect against hackers seeking to infiltrate a specific system. Because of Unresolved firewall issues, a firm becomes open to exploitation, allowing viruses to infect networked devices and cybercriminals to execute harmful code remotely.

Total network failure is one of the worst-case scenarios that can occur in the unresolved firewall issues. Malicious criminals can effectively shut down your organization if you do not provide proper protection. And this can have disastrous consequences for your company. Not only might you lose data, but it can also take days or even weeks to get your systems back up and running.

What are the Biggest Issues with Firewalls?

Firewalls are a fundamental component of every company's cybersecurity architecture. Firewalls, on the other hand, should never be regarded as the be-all and end-all solution for your company's cybersecurity concerns. Yes, they are useful, but there are a few drawbacks to relying solely on firewalls to safeguard your business.

What are some of the most common firewall issues to be aware of? Here's a rundown of the problems.

  • Insider Threats: A perimeter firewall is designed to keep attacks that originate outside of your network at bay. So, what happens when the onslaught begins from within? After all, the attacker is already on your system, therefore the perimeter firewall is rendered ineffective.
  • Missed Security Patches: This is a problem that occurs when network firewall software is not properly controlled. There are vulnerabilities in any software program that attackers can exploit; this is true of firewall applications as well as any other piece of software. When firewall providers uncover these vulnerabilities, they normally work quickly to develop a patch that fixes the problem.
  • Configuration Mistakes: Even if your network has a firewall and all of the newest vulnerability updates, it might still cause issues if the firewall's configuration settings conflict. In some circumstances, this can result in a decrease in network performance, while in others, a firewall may fail to provide protection.
  • A Lack of Deep Packet Inspection: Layer 7 (or "deep packet") inspection is a stringent inspection mode used by next-generation firewalls to evaluate the contents of an information packet before authorizing or refusing its passage to or from a system. Less complex firewalls may just examine the point of origin and destination of a data packet before allowing or refusing a request -information that an attacker might easily spoof to fool your network firewall. The ideal solution to this problem is to employ a firewall capable of doing deep packet inspection to check information packets for known malware and reject it.
  • DDoS attacks: DDoS attacks are a popular attack method because they are both extremely effective and relatively inexpensive to carry out. The primary purpose is to overwhelm a defender's resources, resulting in a shutdown or protracted incapacity to provide services. Protocol attacks are one type of attack that aims to deplete the resources of firewalls and load balancers in order to prevent them from processing legal traffic. While firewalls can help to combat some types of DDoS attacks, they can also be overwhelmed by protocol attacks. There is no simple solution to DDoS attacks because there are several attack tactics that might exploit various holes in your company's network infrastructure.