Top 10 Network Security Best Practices

Network security is a critical component of any organization’s IT infrastructure. With cyber threats growing in sophistication, implementing robust network security measures has become more important than ever. In this article, I will provide an in-depth look at the top 10 best practices that organizations should follow to secure their networks.

1. Keep All Software Up-To-Date

Keeping all software on servers, workstations, and mobile devices fully updated is one of the most fundamental network security best practices. Software vendors regularly release patches to fix vulnerabilities that could be exploited by attackers. Failing to promptly install these updates leaves you exposed.

Some key steps to keep software updated include:

• Use automation to check for and deploy updates across all devices. Manual updating is inefficient.
• Prioritize critical security patches for immediate deployment.
• Test patches before deployment, especially for custom applications.
• Maintain awareness of endpoints or systems that may have fallen off patch management.

Staying on top of software updates takes continuous effort, but is well worth it to mitigate risks.

2. Secure Network Perimeters

Traditional network perimeters focused on securing the corporate network from the public internet. But networks have become more complex with the rise of cloud, mobile and IoT. Still, locking down perimeter access remains crucial.

Steps to secure network perimeters involve:

• Use firewalls to restrict inbound and outbound connections to only necessary ports and protocols.
• Implement DMZ architecture with web servers in the DMZ to add a layer between the internet and internal network.
• Require VPN for any remote access into the network. Use multi-factor authentication.
• Use advanced threat protection on perimeter devices to identify command and control activity, exploits and malware.
• Monitor traffic flows across the perimeter to detect anomalies indicative of threats.

The network perimeter must be fortified to prevent unauthorized access from the outside.

3. Shield Internet-Facing Applications

Applications accessible from the internet expand the attack surface. Such applications should be isolated and enhanced with additional safeguards.

Key practices for internet-facing apps:

• Place applications in a DMZ to restrict access to the internal network.
• Obscure actual application infrastructure details through hiding server banners.
• Require strong authentication for application access.
• Validate and sanitize all input to applications.
• Adhere to secure coding practices for in-house applications.
• Perform regular vulnerability scans and penetration tests.
• Monitor application performance metrics and logs for abnormalities.
• Maintain separate security infrastructure for internet-facing apps.

Extra layers of protection are necessary for applications reachable from the public internet.

4. Secure Endpoints

Endpoints such as desktops, laptops, servers, and mobile devices directly interact with users and access critical data assets. Keeping endpoints secure is imperative.

Key endpoint security measures:

• Implement antivirus/anti-malware software to block known threats
• Use host-based firewalls and IPS to catch malicious activity
• Encrypt devices to protect from data loss if stolen
• Manage devices with tools like SCCM for centralized policies and control
• Deploy endpoint detection and response (EDR) for advanced threat monitoring
• Maintain rigorous patch management on endpoints
• Develop secure system imaging for rapid rebuild if compromised
• Enforce strong passwords and multi-factor authentication
• Provide limited local admin rights to limit damage from malware

Vigilance around endpoint security reduces the attack surface from insider risks.

5. Control Access with Least Privilege

Limiting user access with least privilege restraints the damage from compromised accounts. Users should only have access to the specific applications, systems and data they absolutely need for their role.

Steps to implement least privilege:

• Classify data by sensitivity level and establish protection requirements.
• Integrate identity and access management (IAM) into applications.
• Enforce separation of duties for privileged users.
• Configure user groups, roles and policies to align with principle of least privilege.
• Use just-in-time privilege elevation only when needed.
• Implement strong access controls and auditing on databases with sensitive information.
• Prevent administrative credentials from being used on non-privileged systems.
• Mandate periodic access reviews to weed out unnecessary access.

Least privilege minimizes the attack surface by removing unnecessary access.

6. Encrypt Sensitive Data

If sensitive data falls into the wrong hands it can lead to catastrophic security incidents. Encrypting data at rest and in transit prevents unauthorized access if networks are infiltrated.

Key encryption best practices:

• Classify data into sensitivity levels based on risk impact.
• Implement data-at-rest encryption using self-encrypting drives, file/folder encryption and database encryption.
• Encrypt data in transit traversing networks and the internet using protocols like TLS, SSL, SSH, SFTP or IPsec VPNs.
• Maintain encryption keys securely with a key management system separate from encrypted data stores.
• Use application-layer encryption for highly sensitive data like health records or financial info.
• Mask sensitive data when displayed or printed using tokenization.
• Mandate encrypted communication channels for employees.

Encrypting sensitive data is a critical last line of defense.

7. Harden Internal Network Segments

The internal network should be segmented into subnets based on role and sensitivity. Traffic between segments should then be restricted using access control policies.

Steps to properly segment and lockdown internal networks:

• Logically separate networks by business function or data sensitivity using VLANs or virtual routing.
• Filter traffic between network zones to allow only necessary communication.
• Implement internal firewalls and IPS to monitor lateral threat movement.
• Use private IP addressing between segments to hide network architecture.
• Eliminate single points of failure on critical network infrastructure.
• Authenticate all system-to-system connections internally using mutual TLS or certificates.
• Build a separate management network for administrative traffic.

Segmenting the network and locking down communication decreases exposure.

8. Log and Monitor Everything

Extensive logging enables security teams to look back at events leading up to an incident and rapidly respond. Strict log management is vital.

Key aspects of logging and monitoring:

• Send logs from all critical infrastructure to a central security information event management (SIEM) system.
• Normalize and correlate logs across network, applications and endpoints.
• Raise alerts for anomalies and high-risk events like failed logins.
• Retain logs for an extended period to allow historical analysis.
• Monitor systems, network traffic, applications and user activity in real time.
• Gain visibility across cloud environments and IoT.
• Perform real-time alerting and incident response for critical threats.

Robust logging and monitoring enables rapid incident detection and response.

9. Train Employees on Security Awareness

Employees interact with systems and data every day, so making security part of their daily thought process through training minimizes risks from human error and social engineering.

Key considerations for security awareness training:

• Establish training for new hires and annual refreshers for all employees.
• Send simulated phishing and ransomware emails to test readiness.
• Ensure training covers diverse topics like password security, social engineering, safe web use and data handling.
• Frame training from a positive standpoint on protecting assets.
• Reach employees through posters, events, policies and periodic short lessons.
• Reward security mindfulness among employees.

An informed workforce is a huge asset in identifying and responding to security incidents.

10. Perform Proactive Assessments

Proactively hunt for security gaps through audits, controls analysis, and exercises like penetration testing and red teaming. Assessment findings highlight areas for improvement.

Key proactive assessment activities:

• Conduct scheduled vulnerability scanning of networks, web apps, databases and endpoints.
• Hire external partners to perform in-depth penetration testing that mimics real attacks.
• Analyze security controls to ensure adequate risk mitigation.
• Test incident response processes with scenario exercises.
• Assess compliance against security regulations and standards.
• Participate in cyber threat intelligence sharing programs.
• Research attack techniques and adversaries targeting your industry.

Proactive assessments build resilience by revealing flaws before they are exploited in an attack.

Following these in-depth network security best practices reduces risk across the attack surface. They reflect a defense-in-depth approach that secures the perimeter, protects critical assets, monitors for threats and fosters a vigilant culture. Organizations that embody these practices greatly improve their security posture in the face of increasingly sophisticated cyber attacks.