Securing the Network Layer Against Malicious Attacks

The costs associated with cybercrime are already staggering and continue to rise sharply. According to the Global Cybercrime Report 2025, the projected global cost of cybercrime is $11.9 trillion USD by 2026, rising to $19.7 trillion by 2030. But even that figure may not capture all costs, due to underreporting and other factors. The true financial impact varies widely across industries and organizations, especially when factoring in downtime, recovery, and reputational damage.

Being proactive can help mitigate the potential impact of cybercrime. A secure network is the first line of defense against malicious attacks. This applies to both cloud and on-premise environments, where the network layer serves as the primary checkpoint controlling what reaches your systems in the first place.

Baseline Security Measures: Router, Firewall, and Switch Configurations 

Today’s threat landscape is being reshaped by Artificial Intelligence (AI) on both sides: attackers use AI to automate scanning and identify weaknesses faster, while defenders rely on AI to spot unusual activity and respond before damage occurs. This makes strong network-layer protection essential for reducing business risk. That protection starts with fundamental steps that should be taken as a baseline for all scenarios.

Router Security

• Router operating system is up to date on all security patches
• Unused ports are blocked
• Unused interfaces and services are disabled
• Logging is enabled and auditing of unusual activity occurs
• Packet filtering is enabled

 Firewall Security

• Firewall software is up to date on all security patches
• Firewalls are placed between all untrusted networks
• Logging is enabled and auditing of unusual activity occurs
• Packet filtering is enabled
• Consider upgrading to next-generation firewalls which incorporate behavior-based analysis or machine learning to flag unusual patterns; an advantage over older, signature-based tools that only detect known threats.

 Switch Security

• Switch software is up to date on all security patches
• Unused interfaces and services are disabled
• Switch traffic is encrypted
• Ensure switch settings are consistently applied across cloud-integrated environments to avoid gaps created by hybrid architecture.

With an effective baseline network security plan in place, there are additional countermeasures to address specific kinds of threats. Common network level threats include information gathering, sniffing, spoofing and distributed denial of service (DDoS).

Information Gathering

The information gathering threat involves attackers attempting to gain information about your system so they can determine where weak points exist. Attackers increasingly use automated tools, including AI, to scan systems continuously and assemble a picture of what a business is running—even when the business is unaware it is being observed.

For example, attackers may scan network entry points, cloud resources, exposed services, outdated components, or configuration gaps. If you happen to be running a version of an application or operating system with a known exploit and an attacker discovers this, expect the attacker to mount an attack using that information.

Hybrid cloud environments can unintentionally make this easier if settings differ between cloud and on-prem systems, creating blind spots that automated scanning tools can quickly exploit.

Best practice countermeasures include:

• Use a firewall to block services which should not be publicly exposed.
• When services must be exposed, use generic service banners which give away as little information about the service as possible.
• Regularly inventory exposed services and remove or remediate those not aligned with business needs.

Network Sniffing

Network sniffing is the act of intercepting and monitoring your network traffic.

Attackers increasingly look for private information being transmitted in plain-text, clear-text passwords, and weak encryption which can be cracked.

In hybrid cloud setups, sniffing often targets misconfigured connections between cloud workloads and on-prem systems, especially where older systems still rely on outdated protocols. Ensuring consistent encryption across all environments is essential.

Best practice countermeasures include:

• Prevent unauthorized devices from joining the network by enforcing restricted access and using modern encryption standards.
• Monitor all devices on your network and the software installed on them.
• Use strong encryption on any traffic that needs to be private.
• Always assume that your network traffic is being intercepted by malicious parties and secure it based on that assumption.

Spoofing

Spoofing is the act of faking the true identity of packets to make it look like the packet came from a trusted or different source.

Spoofed packets may be used for purposes such as hiding the identity of denial of service attacks or assuming the identity of sources which have access to private areas of your network.

Spoofing risks increase in hybrid environments where cloud and on-prem systems use different identity, routing, or segmentation rules. Inconsistent policies can unintentionally allow fraudulent traffic to appear legitimate.

Best practice countermeasures include:

• Ingress filtering - filtering packets coming from a network which should not be sending packets with that IP.
• Egress filtering - denying the sending of any packets outbound from the network which are not on a tightly controlled whitelist.

Distributed Denial of Service (DDoS)

Distributed Denial of Service (DDoS) attacks are one of the most prolific threats to networks.

The goal of a DDoS attack is to deny legitimate users from accessing the servers which host your web application. Common types of DDoS attacks include packet floods and service buffer overflow attacks. They are designed to overwhelm a target system or network by flooding it with a massive volume of traffic from multiple sources. This can disrupt network services and cause service outages.

Other types of DDoS attacks rely on specific flaws in various applications and operating systems, such as the teardrop attack which can crash some older operating systems.

Best practice countermeasures include:

• Properly configured routers, firewalls, and switches.
• Keeping the operating systems, services and applications on the network updated with the latest security patches.
• Utilize dedicated DDoS mitigation services (many utilize AI) or hardware appliances that can detect and mitigate volumetric, protocol, and application layer attacks.
• Continuously monitor network traffic for abnormal patterns or sudden spikes in traffic volume, and take appropriate actions based on predefined policies.

To Recap

To counter network layer security threats, implementing best practices and security measures can help mitigate risks. That begins with a sound baseline security plan for the network's router, firewall, and switch configurations. Additional steps can be taken to prevent specific kinds of threats. Making a system’s first line of defense, the network layer, secure and resilient against modern threats (including AI-assisted reconnaissance, hybrid-cloud misconfigurations, spoofing attempts, and increasingly automated DDoS attacks) is essential.