How To Prevent Firewall Breaches (The 2024 Guide)

Properly configured firewalls are vital in any comprehensive cybersecurity strategy. However, even the most robust configurations can be vulnerable to exploitation by attackers. 

No single security measure can offer absolute protection against all cyber threats and data security risks. To mitigate these risks, it’s crucial to understand how cybercriminals exploit firewall vulnerabilities.

The more you know about their tactics, techniques, and procedures, the better-equipped you are to implement security policies that successfully block unauthorized access to network assets.

In this guide, you’ll understand the common cyber threats that target enterprise firewall systems with the goal of helping you understand how attackers exploit misconfigurations and human vulnerabilities. Use this information to protect your network from a firewall breach. 

Understanding 6 Tactics Cybercriminals Use to Breach Firewalls

1. DNS Leaks

Your firewall’s primary use is making sure unauthorized users do not gain access to your private network and the sensitive information it contains. But firewall rules can go both ways – preventing sensitive data from leaving the network is just as important.

If enterprise security teams neglect to configure their firewalls to inspect outgoing traffic, cybercriminals can intercept this traffic and use it to find gaps in your security systems. DNS traffic is particularly susceptible to this approach because it shows a list of websites users on your network regularly visit.

A hacker could use this information to create a spoofed version of a frequently visited website. For example, they might notice your organization’s employees visit a third-party website to attend training webinars. Registering a fake version of the training website and collecting employee login credentials would be simple. If your firewall doesn’t inspect DNS data and confirm connections to new IP addresses, you may never know.

DNS leaks may also reveal the IP addresses and endpoint metadata of the device used to make an outgoing connection. This would give cybercriminals the ability to see what kind of hardware your organization’s employees use to connect to external websites. With that information in hand, impersonating managed service providers or other third-party partners is easy. Some DNS leaks even contain timestamp data, telling attackers exactly when users requested access to external web assets.

How to protect yourself against DNS leaks

Proper firewall configuration is key to preventing DNS-related security incidents. Your organization’s firewalls should provide observability and access control to both incoming and outgoing traffic. Connections to servers known for hosting malware and cybercrime assets should be blocked entirely. Connections to servers without a known reputation should be monitored closely. In a Zero Trust environment, even connections to known servers should benefit from scrutiny using an identity-based security framework.

Don’t forget that apps can connect to external resources, too. Consider deploying web application firewalls configured to prevent DNS leaks when connecting to third-party assets and servers.

You may also wish to update your security policy to require employees to use VPNs when connecting to external resources. An encrypted VPN connection can prevent DNS information from leaking, making it much harder for cybercriminals to conduct reconnaissance on potential targets using DNS data.

2. Encrypted Injection Attacks

Older, simpler firewalls analyze traffic by looking at different kinds of data packet metadata. This provides clear evidence of certain denial-of-service attacks, clear violations of network security policy, and some forms of malware and ransomware. They do not conduct deep packet inspection to identify the kind of content passing through the firewall.

This provides cybercriminals with an easy way to bypass firewall rules and intrusion prevention systems – encryption. If malicious content is encrypted before it hits the firewall, it may go unnoticed by simple firewall rules. Only next-generation firewalls capable of handling encrypted data packets can determine whether this kind of traffic is secure or not.

Cybercriminals often deliver encrypted injection attacks through email. Phishing emails may trick users into clicking on a malicious link that injects encrypted code into the endpoint device. The script won’t decode and run until after it passes the data security threshold posed by the firewall. After that, it is free to search for personal data, credit card information, and more.

Many of these attacks will also bypass antivirus controls that don’t know how to handle encrypted data. Task automation solutions like Windows PowerShell are also susceptible to these kinds of attacks. Even sophisticated detection-based security solutions may fail to recognize encrypted injection attacks if they don’t have the keys necessary to decrypt incoming data.

How to protect yourself against encrypted injection attacks

Deep packet inspection is one of the most valuable features next-generation firewalls provide to security teams. Industry-leading firewall vendors equip their products with the ability to decrypt and inspect traffic. This allows the firewall to prevent malicious content from entering the network through encrypted traffic, and it can also prevent sensitive encrypted data – like login credentials – from leaving the network.

These capabilities are unique to next-generation firewalls and can’t be easily replaced with other solutions. Manufacturers and developers have to equip their firewalls with public-key cryptography capabilities and obtain data from certificate authorities in order to inspect encrypted traffic and do this.

3. Compromised Public Wi-Fi

Public Wi-Fi networks are a well-known security threat for individuals and organizations alike. Anyone who logs into a password-protected account on public Wi-Fi at an airport or coffee shop runs the risk of sending their authentication information directly to hackers.

Compromised public Wi-Fi also presents a lesser-known threat to security teams at enterprise organizations – it may help hackers breach firewalls.

If a remote employee logs into a business account or other asset from a compromised public Wi-Fi connection, hackers can see all the data transmitted through that connection. This may give them the ability to steal account login details or spoof endpoint devices and defeat multi-factor authentication.

Even password-protected private Wi-Fi connections can be abused in this way. Some Wi-Fi networks still use outdated WEP and WPA security protocols that have well-known vulnerabilities. Exploiting these weaknesses to take control of a WEP or WPA-protected network is trivial for hackers. The newer WPA2 and WPA3 standards are much more resilient against these kinds of attacks.

While public Wi-Fi dangers usually bring remote workers and third-party service vendors to mind, on-premises networks are just as susceptible. Nothing prevents a hacker from gaining access to public Wi-Fi networks in retail stores, receptions, or other areas frequented by customers and employees.

How to protect yourself against compromised public Wi-Fi attacks

First, you must enforce security policies that only allow Wi-Fi traffic secured by WPA2 and WPA3 protocols. Hardware Wi-Fi routers that do not support these protocols must be replaced. This grants a minimum level of security to protected Wi-Fi networks.

Next, all remote connections made over public Wi-Fi networks must be made using a secure VPN. This will encrypt the data that the public Wi-Fi router handles, making it impossible for a hacker to intercept without gaining access to the VPN’s secret decryption key. This doesn’t guarantee your network will be safe from attacks, but it improves your security posture considerably.

4. IoT Infrastructure Attacks

Smartwatches, voice-operated speakers, and many automated office products make up the Internet of Things (IoT) segment of your network. Your organization may be using cloud-enriched access control systems, cost-efficient smart heating systems, and much more. Any Wi-Fi-enabled hardware capable of automation can safely be included in this category.

However, these devices often fly under the radar of security team’s detection tools, which often focus on user traffic. If hackers compromise one of these devices, they may be able to move laterally through the network until they arrive at a segment that handles sensitive information.

This process can take time, which is why many incident response teams do not consider suspicious IoT traffic to be a high-severity issue. IoT endpoints themselves rarely process sensitive data on their own, so it’s easy to overlook potential vulnerabilities and even ignore active attacks as long as the organization’s mission-critical assets aren’t impacted.

However, hackers can expand their control over IoT devices and transform them into botnets capable of running denial-of-service attacks. These distributed denial-of-service (DDoS) attacks are much larger and more dangerous, and they are growing in popularity among cybercriminals. Botnet traffic associated with DDoS attacks on IoT networks has increased five-fold over the past year, showing just how promising it is for hackers.

How to protect yourself against IoT infrastructure attacks

Proper network segmentation is vital for preventing IoT infrastructure attacks. Your organization’s IoT devices should be secured on a network segment that is isolated from the rest of the network. If attackers do compromise the entire network, you should be protected from the risk of losing sensitive data from critical business assets.

Ideally, this protection will be enforced with a strong set of firewalls managing the connection between your IoT subnetwork and the rest of your network. You may need to create custom rules that take your unique security risk profile and fleet of internet-connected devices into account. There are very few situations in which one-size-fits-all rulemaking works, and this is not one of them.

All IoT devices – no matter how small or insignificant – should be protected by your firewall and other cybersecurity solutions. Never let these devices connect directly to the Internet through an unsecured channel. If they do, they provide attackers with a clear path to circumvent your firewalls and gain access to the rest of your network with ease.

5. Social Engineering and Phishing

Social engineering attacks refer to a broad range of deceptive practices used by hackers to gain access to victims’ assets. What makes this approach special is that it does not necessarily depend on technical expertise. Instead of trying to hack your systems, cybercriminals are trying to hack your employees and company policies to carry out their attacks.

Email phishing is one of the most common examples. In a typical phishing attack, hackers may spoof an email server to make it look like they are sending emails from a high-level executive in the company you work for. They can then impersonate this executive and demand junior accountants pay fictitious invoices or send sensitive customer data to email accounts controlled by threat actors.

Other forms of social engineering can use your organization’s tech support line against itself. Attackers may pretend to represent large customer accounts and will leverage this ruse to gain information about how your company works. They may impersonate a third-party vendor and request confidential information that the vendor would normally have access to.

These attacks span the range from simple trickery to elaborate confidence scams. Protecting against them can be incredibly challenging, and your firewall capabilities can make a significant difference in your overall state of readiness.

How to protect yourself against social engineering attacks

Employee training is the top priority for protecting against social engineering attacks. When employees understand the company’s operating procedures and security policies, it’s much harder for social engineers to trick them. Ideally, training should also include in-depth examples of how phishing attacks work, what they look like, and what steps employees should take when contacted by people they don’t trust.

6. Sandbox Exploits

Many organizations use sandbox solutions to prevent file-based malware attacks. Sandboxes work by taking suspicious files and email attachments and opening them in a secure virtual environment before releasing them to users. The sandbox solution will observe how the file behaves and quarantine any file that shows malicious activity.

In theory, this provides a powerful layer of defense against file-based attacks. But in practice, cybercriminals are well aware of how to bypass these solutions.

For example, many sandbox solutions can’t open files over a certain size. Hackers who attach malicious code to large files can easily get through. Additionally, many forms of malware do not start executing malicious tasks the second they are activated. This delay can provide just enough of a buffer to get through a sandbox system. Some sophisticated forms of malware can even detect when they are being run in a sandbox environment – and will play the part of an innocent program until they are let loose inside the network.

How to protect yourself against sandbox exploits

Many next-generation firewalls include cloud-enabled sandboxing capable of running programs of arbitrary size for a potentially unlimited amount of time. More sophisticated sandbox solutions go to great lengths to mimic the system specifications of an actual endpoint so malware won’t know it is being run in a virtual environment.

Organizations may also be able to overcome the limitations of the sandbox approach using Content Disarm and Reconstruction (CDR) techniques. This approach keeps potentially malicious files off the network entirely and only allows a reconstructed version of the file to enter the network. Since the new file is constructed from scratch, it will not contain any malware that may have been attached to the original file.

Prevent firewall breaches with AlgoSec

Managing firewalls manually can be overwhelming and time-consuming – especially when dealing with multiple firewall solutions. With the help of a firewall management solution, you easily configure firewall rules and manage configurations from a single dashboard. 

AlgoSec’s powerful firewall management solution integrates with your firewalls to deliver unified firewall policy management from a single location, thus streamlining the entire process. With AlgoSec, you can maintain clear visibility of your firewall ruleset, automate the management process, assess risk & optimize rulesets, streamline audit preparation & ensure compliance, and use APIs to access many features through web services.