Main Firewall Threats & Challenges
Here are the most common firewall threats that can exploit the firewall limitations.
#1. Insider Threats
One of the primary shortcomings of enterprise firewalls is their inability to address insider threats.
This arises when trusted individuals within the organization misuse their access, either intentionally or accidentally. Since firewalls typically operate on predefined external-internal traffic rules, they lack the ability to monitor lateral movements or suspicious activities from authenticated users.
#2. DDoS Attacks
Distributed Denial of Service (DDoS) attacks flood networks with excessive traffic, with the aim to disrupt services. While firewalls can block traffic from known malicious IPs, they’re easily sidestepped by attackers distributing requests from different devices.
Modern DDoS attacks frequently leverage botnets and spoofed IP addresses – bypassing firewall filtering mechanisms.
#3. Encrypted Traffic
Encryption protocols like TLS are increasingly central to public networks. But, they continue to thwart traditional firewalls from inspecting packets for malicious payloads. Many enterprise firewalls lack robust SSL/TLS decryption capabilities due to the high computational overhead involved.
This limitation necessitates the use of dedicated tools, such as:
- SSL decryption proxies
- Inline decryption appliances
(All of which can add latency to enterprise networks.)
These limitations don’t negate the raw security benefits of firewalls: they’re just facets of today’s attack surface.
Core Firewall Vulnerabilities
It’s not just firewalls’ inherent limitations that you need to stay mindful of: like any piece of business firmware, firewalls can fall foul of marauding bad actors. While the last three threats are blind spots of firewalls, the following vulnerabilities target the firewall appliance itself.
They focus on the flaws in the design, configuration, or implementation that attackers can exploit
#4. Command Injection Vulnerabilities
This type of vulnerability takes advantage of firewalls’ innate customizability: rather than legitimate setting changes, however, command injection sees attackers hide operating-system-level commands in benign-looking inputs. Making this more of a challenge is the fact that firewalls are at the forefront of an organization’s network:
- They’re the device most exposed to the public internet
- The hardest to gain security visibility over
Reducing the risk of random third parties sending commands its way is made possible by account privileges. Only high-privilege, admin accounts should be able to execute changes. This is why command injection vulnerabilities that bypass authentication and skip directly to root access are exceedingly dangerous.
Root access command injection allows anyone – even when NOT logged into the admin account – to run code.
#5. Cleartext Credentials Stored in Logs
Since firewalls authenticate their users, they interact regularly with credentials. Remember how we said the firewall can be uniquely difficult to protect, given its position right at the edge of the network?
Logs are a way to monitor what decisions and rules a firewall is operating under.
While useful for the rest of an enterprise’s security efforts, these logs also monitor any actions administrators are making – including authentication instances. When improperly formatted, this can result in passwords being included in firewall log data.
Attackers who gain access to log files, whether through other vulnerabilities or insider access, can then retrieve these credentials, and amplify the attack or launch breaches.
#6. Denial of Service
Since firewalls handle devices’ connections to the Internet, they represent a target for Denial of Service. This was seen in a recent Denial of Service vulnerability in Cisco software, CVE-2024-20353.
The flaw stems from the improper handling of specific crafted network packets by the web server components of Cisco ASA and FTD. These components are responsible for processing VPN connections and management interface traffic. The issue allows an attacker to:
- Send specially crafted packets to these servers
- This triggers an error that forces the affected device to restart unexpectedly.
VPN connections, firewalls, and other critical services provided by the device are interrupted during the reboot, impacting users and causing downtime for enterprises reliant on these systems
4 Best Practices for Firewall Security
Keeping a firewall well-maintained can take a lot of time and effort. But, the cost and effort of a breach is far higher. That’s why leveraging best practices to have a well-functioning firewall can lead to more efficient management.
#1: Tightly Tune Rules
Tightly tuning firewall rules involves creating and enforcing access policies that adhere strictly to the principle of least privilege (PoLP). This means defining rules that allow only necessary traffic while blocking all other connections by default.
Overly permissive rules or unused configurations can become attack vectors.
Regularly auditing and optimizing these rules ensures they remain relevant to the current network architecture and operational requirements.
#2: Update Securely
Keeping firewall software and associated tools up to date is critical to addressing vulnerabilities and improving functionality. Keep an eye on why a patch is being pushed: if it’s following a vuln publication, it becomes vital to update as soon as possible, and potentially rotate all usernames, passwords, and API keys associated with the tool and processed by firewalls.
This ensures that any credentials potentially exposed during a vulnerability window are no longer usable.
For environments where immediate updates aren’t feasible, administrators should restrict access to the firewall, limiting exposure to authorized users, hosts, or networks.
#3: Verify Updates
When a critical vulnerability is identified, a race begins between defenders and attackers:
- Threat actors monitor vulnerability disclosures
- Threat actors rapidly develop proof-of-concept (PoC) exploit code
- Threat actors use it against unpatched systems.
You must prioritize applying security patches as soon as they’re released, particularly for zero-day vulnerabilities.
After patching, administrators should use PoCs to test and verify that the patch or mitigation is effective – making sure the firewall and other components are protected.
#4: Conduct Penetration Testing
Penetration testing is an essential part of firewall security. Regular pen tests help identify:
- Weaknesses in firewall configurations
- Unpatched vulnerabilities
- Potential gaps in rule enforcement
Simulating real-world attacks allows security teams to assess how well the firewall defends against specific threats and provides actionable insights to strengthen overall security posture. By combining pen tests with other best practices, you proactively discover and resolve issues before attackers exploit them.
Protect Against DDoS, Insider Threats, and Encryption with Quantum Force
Check Point Quantum offers a high-throughput firewall based on an accessible, unified network policy management platform. It’s designed to streamline the oversight of firewalls, applications, users, and workloads with real-time threat visibility, large-scale event logging, and automated reporting to enhance security operations.
Offered both as firewall software and as a hardware appliance, its versatility makes it one of the most adaptable next-generation firewalls on the market today.
Supporting both on-premises and public/private cloud environments, Quantum offers:
- Advanced automation for workflows and API
- Device compliance checks
- Preconfigured templates for automated threat prevention
This combined with the versatility of the Quantum Force series, which offers ten appliance options tailored to various throughput and performance needs, Check Point provides solutions for every environment.
Schedule a step-by-step demo to see how it can fit your security needs.
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