What Is Network Device Hardening? Standards & Best Practices
Network device hardening is the process by which you secure routers, switches, firewalls, and other digital infrastructure by minimising vulnerabilities, disabling superfluous services, and mandating configuration controls.
Adhering to the UK government’s system of lockdown and hardening standards should ensure devices are configured for maximum resilience to cyber threats and unauthorised access.
In this blog, we discuss why network device hardening is critical, what the standards are for network device hardening, and the core principles of network device hardening.
Network Device Hardening: Critical for Enterprise Security
At its core, network hardening is about reducing the ‘attack surface’ across your infrastructure. It involves identifying and removing weaknesses in your configuration, access controls, or outdated firmware that attackers may use to access your network.
For organisations, this is critical. Network devices are the backbone of the connection between a system, users, and cloud infrastructure. If a breach occurred, attackers would have lateral movement options, visibility throughout the entire network, and could persist within a network.
The UK Ministry of Justice guidance defines two essential principles:
- Locked-down: Every unnecessary or non-essential service or capability is switched off, or reduced to the bare minimum functionality.
- Hardened system: System options and capabilities should be configured for maximum resistance to attack or unauthorised use.
For IT leaders, this is closely aligned with strategies like “zero trust” and “defence-in-depth”. These strategies tell us that nothing should be assumed to be secure by default, and that every configuration decision should contribute to reducing risk.
Hardening Standards for Network Devices
Hardening standards are intended to enforce consistency and compliance with broader security frameworks. The Ministry of Justice’s system of lockdown and hardening provides a benchmark for organisations. Its general procedures include:
- BIOS lockdown
- Removal of unnecessary applications and services
- Disabling auto-run of data on remote media devices
- Time and date configured to central servers
- Desktops and servers to lock after 5 minutes of inactivity
- Users without administration privileges will not have access to system settings or utilities
The guide highlights that hardening is not intended to be vendor-specific; it should be applied alongside platform-level best practices, with a system of continuous validation. For organisations working in regulated sectors, meeting these standards ensures both operational resilience and readiness for audits.
Core Principles of Network Device Hardening
Implementation relies on a set of consistent principles. The following are widely accepted framework principles by government and industry.
Minimisation of Attack Surface
Firstly, remove anything that is not explicitly required. Finding what can access your network is an entire process on its own; it is called IT asset discovery, and you can read about it on our blog: ‘What is IT asset discovery?’.
The removal process involves:
- Disabling unused ports and interfaces
- Removing redundant services and applications
- Restricting management access paths
Authentication and Access Control
Having control over who can access networks is critical. Hardening requires:
- Role-based access control (RBAC)
- Multi-factor authentication (MFA)
- Centralised authentication systems
Without access control, even hardened configurations can be bypassed by using acquired legitimate credentials.
Patch and Vulnerability Management
Unpatched firmware is one of the most common entry points for attackers. Device hardening requires:
- Continuous monitoring of vendor advisories
- Regular firmware updates
- Proactive vulnerability remediation
Historically, unpatched firmware has led to major breaches, reinforcing the importance of technology’s lifecycle management.
Encryption and Secure Protocols
All management and data traffic should be secured:
- Replace insecure protocols with encrypted alternatives
- Enforce TLS for management interfaces
- Encrypt sensitive configuration data
Monitoring, Logging, and Auditability
Hardening ultimately needs visibility. Companies should be logging and monitoring:
- Detect suspicious activity
- Support incident response
- Provide audit trails for compliance
This aligns with the National Cyber Security Centre guidance around system administration and monitoring practices.
Common Challenges Applying Network Hardening at Scale
Having clear standards and principles is essential, but applying them across an entire organisation can present several challenges.
Inconsistent Environments
Before clear guidance is implemented, devices will often evolve differently across an organisation. This can create gaps that attackers can exploit.
Legacy Infrastructure
An old device might not be supported and lack more modern protections, like strong encryption. This may make hardening difficult without new hardware.
Operational Risk and Downtime
Applying hardening measures may lead to downtime. For some environments, this could create tension between productivity and security.
Evolving Threats
Hardening needs to be a continuous process. New attack techniques appear, so configurations must be reviewed and updated.
Beyond Configuration to Strategic Hardening
Network device hardening is a strategic requirement for protecting modern IT environments.
By aligning with hardening standards for network devices, like the UK government’s system lockdown approach, organisations can ensure their infrastructure is secure and resilient against evolving threats.
At Net Consulting, we support IT leaders by designing and implementing robust network hardening strategies. Whether modernising legacy infrastructure, enforcing consistent standards, or integrating hardening into a security framework, we are here to help.
Get in touch today about our Security Device Hardening service to strengthen your network across your organisation.
