Level Up Your Network Defense: Maturity Steps to Secure Your Infrastructure

Your network security is like the Earth itself, a layered system where each component plays a critical role in maintaining stability. At the surface, the crust represents your visible defenses: firewalls, antivirus software, and access controls that form the first line of protection. Beneath this lies the mantle, a layer of advanced processes like encryption, vulnerability management, and secure configurations that bolster your defenses. But the true power lies at the core — your incident response strategy, threat intelligence, and resilience planning. Just as the world's core generates the heat and magnetic fields that shield the planet from harmful solar winds, a mature network defense relies on its core strategies to protect your enterprise from evolving cyber threats. This article delves into the layers of network security maturity, guiding you to build a defense as resilient and dynamic as the Earth.

Define an Enterprise Network Security Policy

Defining a clear, comprehensive network security policy is the foundation of your enterprise's journey toward maturity. This document acts as a compass, aligning your team’s efforts, guiding decision-making, and setting expectations for how data, systems, and users are protected. Without it, even the most advanced tools and technologies can fall short, lacking the direction needed to form a cohesive defense.

Implementing these key pillars will help bolster your approach and provide a huge leap forward for your network:

Network Device Passwords

A compromised password on a network device could have devastating, network-wide consequences. Passwords that are used to secure these devices, such as routers, firewalls, and switches, must be held to higher standards than standard user-level or desktop system passwords.

Change Requirements

Passwords must be changed according to your enterprise Password Policy. Additionally, the following requirements apply to changing network device passwords:

• If any network device password is suspected to have been compromised, all network device passwords must be changed immediately.
• Vendor default passwords must be changed when new devices are put into service.

Administrative Password Guidelines

Administrative (also known as "root") access to systems should be limited to only those who have a legitimate business need for this type of access. This is particularly important for network devices, since administrative changes can have a major effect on the network, and, as such, network security. Additionally, administrative access to network devices should be logged.

Network Device Logging

The logging of certain events is an important component of good network management practice. Logging needs vary depending on the type of network system, and the type of data the system holds. The following sections detail your enterprise's requirements for logging and log review.

Network Devices

Logs from network devices are of interest since these devices control all network traffic and can have a huge impact on  ability to help detect on going malicious activity and investigate after an incident occurs. For example, egress information is valuable to have during the investigation process when determining exfiltration of data.

• Examples: Firewalls, network switches, wireless management controllers, and routers
• Requirement: At a minimum, logging of errors, changes, and login failures is required. Additional logging is encouraged as deemed necessary. No network security passwords should be contained in the logs.

Log Retention

Logs should be retained for a minimum of 90 days. Unless otherwise determined by the head of security or their designee, logs should be considered operational data.

Firewall Configuration and Maintanence Management

Firewalls are arguably the most important component of a sound security strategy. Internet connections and other unsecured networks must be separated from your enterprise network using a firewall.

The following statements apply to the implementation of firewall technology:

• Firewalls must provide secure administrative access (using encryption) with management access limited, if possible, to only networks where management connections would be expected to originate.
• Any resource that is externally facing must have a web application firewall implemented.
• No unnecessary services or applications should be enabled on firewalls.
• The firewall ruleset must be documented and audited periodically, preferably quarterly, by the IT Security. Audits must cover each rule, what it is for, if it is still necessary, and if it can be improved.
• The firewall must log dropped or rejected packets.

Outbound Traffic Filtering

Blocking outbound traffic prevents users from accessing unnecessary, and many times, dangerous services. By specifying exactly what outbound traffic to allow, all other outbound traffic is blocked. This type of filtering would block root kits, viruses, and other malicious tools if a host were to become compromised. This will also prevent remote desktops from accessing the internal network.

Encouraging your team to implement outbound filtering will help prevent sensitive data leaks, maintaining a positive sender reputation, and ensuring compliance with data privacy regulations by actively scanning outgoing emails for malicious content, inappropriate information, and potential spam triggers,. If filtering is deemed possible, only known "good" services should be permitted outbound from the network.

Networking Hardware

Networking hardware, such as routers, switches, hubs, bridges, and access points, should be implemented in a consistent manner. The following statements apply to implementation of networking hardware:

• Networking hardware must provide secure administrative access (using encryption) with management access limited, if possible, to only networks where management connections would be expected to originate.
• Clocks on all network hardware should be synchronized using NTP or another means. Among other benefits, this will aid in problem resolutionand security incident investigation.
• Only specified IT administrators can deploy network devices within the environment.
• When using switches, use VLANs to separate networks if it is reasonable and possible to do so.
• Access control lists should be implemented on network devices that prohibit direct connections to the devices. Exceptions to this are management connections that can be limited to known sources.
• Access to administrative ports on networking hardware should be restricted to known management hosts and otherwise blocked with a firewall or access control list.

Network Patching

Review of available patches must take place every quarter to see what patches for network devices may need to be installed to mitigate risk to the environment. Zero-day vulnerabilities that are discovered are required to be escalated immediately to the head of security for determination of remediation plan.

Intrusion Detection/Intrusion Prevention Systems

Intrusion Detection System (IDS) and Intrusion Prevention System (IPS) technology can be useful in network monitoring and security. The tools differ in that IDS alerts to suspicious activity whereas an IPS blocks the activity. When tuned correctly, IDSs are useful but can generate a large amount of data that must be evaluated for the system to be of any use. IPSs automatically act when they see suspicious events, which can be both good and bad, since legitimate network traffic can be blocked along with malicious traffic.

Procedures must be implemented to review and act on the alerts expediently. For the IPS, procedures must be implemented that provide a mechanism for emergency unblocking if the IPS obstructs legitimate traffic and must be audited periodically.

Security Testing

Security testing, also known as a vulnerability assessment, a security audit, or penetration testing, is an important part of maintaining network security. Security testing can be provided by IT Staff members but is often more effective when performed by a third party with no connection to the day-to-day Information Technology activities.

The following sections detail important requirements for security testing:

Internal Security Testing

Internal security testing does not necessarily refer to testing of the internal network, but rather testing performed by members of the IT team. Internal testing does not replace external testing; however, when external testing is not practical for any reason, or as a supplement to external testing, internal testing can be helpful in assessing the security of the network.

Internal security testing is allowable, but only by employees whose job functions are to assess security, and only with permission of the head of security or their designee. Internal testing should have no measurable negative impact on systems or network performance.

As a rule, "penetration testing," which is the active exploitation of vulnerabilities, is not allowed without approval from the head of security or their designee.

External Security Testing

External security testing, which is tested by a third-party entity, is an excellent way to audit security controls. The head of security or their designee must determine to what extent this testing should be performed, and what systems/applications it should cover.

External testing must not negatively affect network performance during business hours or network security at any time. External security testing be performed annually. If penetration testing is performed, it must not negatively impact systems or data.

Disposal of Information Technology Assets

IT assets, such as network servers and routers, often contain sensitive data about the enterprise's network communications. When such assets are decommissioned, the following guidelines must be followed:

• Any asset tags or stickers that identify  must be removed before disposal.
• Any configuration information must be removed by deletion or, if applicable, resetting the device to factory defaults.
• Hard drives are to be certified as destroyed by a third party.

Network Segmentation

Good network design is integral to network security. By implementing network segmentation, which is separating the network into different segments, this approach will reduce network-wide risk from an attack or malware outbreak. Security can be increased if traffic must traverse additional enforcement/inspection points.

The requires the following regarding network compartmentalization:

Higher Risk Networks

• Examples: Guest network, wireless network
• Requirements: Segmentation of higher risk networks from internal network is required and must be enforced with a firewall or router that provides access controls.

Externally Accessible Systems

• Examples: Email servers, web servers
• Requirements: Segmentation of externally accessible systems from your enterprise's internal network is required and must be enforced with a firewall or router that provides access controls.

Internal Networks

• Examples: Finance, Human Resources
• Requirements: Segmentation of internal networks from one another can improve security as well as reduce chances that a user will access data that they have no right to access.

Network Documentation

Network documentation, specifically as it relates to security, is important for efficient and successful network management. The process of regularly documenting the network ensures that the enterprise has a firm understanding of the network architecture at any time.

At a minimum, network documentation must include:

• Network diagram(s)
• System configurations
• Firewall ruleset
• IP Addresses
• Access Control Lists requires that network documentation be performed and updated on a yearly basis.

Maintenance Windows and Scheduled Downtime

Certain tasks require that network devices be taken offline, either for a simple re-boot, an upgrade, or other maintenance. When this occurs, the IT Staff must perform the tasks before and after normal business hours. Tasks that are deemed "emergency change request," as determined by the head of security or their designee, can be performed at any time.

Change Management

Documenting changes to network devices is a good management practice and can help speed resolution in the event of an incident. The IT Staff should make a reasonable effort to document hardware and/or configuration changes to network devices in a "change log."

Suspected Security Incidents

When a security incident is suspected that may impact a network device, the security team should refer to the Incident Response policy for guidance.

Manufacturer Support Contracts

Outdated products can result in a serious security breach. When purchasing critical hardware or software, must purchase a maintenance plan, support agreement, or software subscription that will allow  to receive updates to the software and/or firmware for a specified period. The plan must meet the following minimum requirements:

• Hardware: The arrangement must allow for repair/replacement of the device within an acceptable period as well as firmware or embedded software updates.
• Software: The arrangement must allow for updates, upgrades, and hot-fixes for a specified period.

Conclusion

Achieving network security maturity is not just about implementing tools and policies; it’s about empowering your team to take ownership of your enterprise’s defense. By fostering a culture of vigilance, collaboration, and continuous learning, you enable your organization to adapt to evolving threats and maintain resilience. The steps outlined in this guide are not a final destination but a roadmap to ongoing growth and improvement. Encourage your team to embrace the challenges, leverage their expertise, and take proactive steps to secure your enterprise’s future.

The time to act is now — empower your team to take the next step toward a secure and thriving environment.