Cybersecurity Policy Template

Network Security Policy

1. Introduction

1.1 Purpose and Scope: This Network Security Policy (NSP) defines the security controls for all organizational networks, including on-premise, cloud-based, and remote access networks. Its purpose is to protect the confidentiality, integrity, and availability (CIA triad) of organizational data during transmission and while at rest within the network infrastructure. This policy applies to all employees, contractors, and third-party vendors accessing the organization's networks.

1.2 Relevance to ISO 27001/2022: This NSP directly supports the implementation of ISO 27001:2022, specifically addressing several Annex A controls related to network security management, including but not limited to:

  • 5.1 Information security policies: This policy itself is a key component of the overall information security management system (ISMS).

  • 5.11 Information security awareness, education and training: Users must be trained on this policy.

  • 5.18 Access control: This policy defines access control measures for network resources.

  • 5.19 Network security: This policy details the core network security controls.

  • 5.20 Security of network services: This addresses securing specific network services.

  • 5.22 Data loss prevention: This policy contributes to preventing data loss during transmission.

  • 5.24 Security incident response: This policy guides actions during network security incidents.

  • 5.25 Information security incident management: The policy aligns with the overall incident management procedures.

2. Key Components

This Network Security Policy includes the following key components:

  • Network Segmentation: Dividing the network into smaller, isolated segments.

  • Firewall Management: Implementing and managing firewalls.

  • Intrusion Detection/Prevention Systems (IDS/IPS): Deploying and monitoring IDS/IPS.

  • Virtual Private Networks (VPNs): Secure remote access.

  • Wireless Network Security: Securing wireless LANs (WLANs).

  • Network Access Control (NAC): Controlling access based on device security posture.

  • Data Loss Prevention (DLP): Preventing sensitive data from leaving the network.

  • Vulnerability Management: Regularly scanning for and mitigating network vulnerabilities.

  • Security Information and Event Management (SIEM): Centralized logging and monitoring.

  • Incident Response: Procedures for handling security incidents.

3. Detailed Content

3.1 Network Segmentation:

  • In-depth explanation: Dividing the network into smaller, logically separated segments limits the impact of a security breach. This reduces the attack surface and prevents lateral movement within the network.

  • Best practices: Segment the network based on criticality, sensitivity of data, and business functions. Use VLANs, firewalls, and routers to create segments.

  • Example: Separate the guest Wi-Fi network from the internal corporate network, and further segment the internal network into departments (e.g., Finance, HR, Development) with separate VLANs and firewalls controlling traffic between them.

  • Common pitfalls: Inadequate segmentation, failure to update segmentation as the network evolves, neglecting to account for cloud-based resources.

3.2 Firewall Management:

  • In-depth explanation: Firewalls control network traffic based on predefined rules. They filter inbound and outbound traffic, blocking unauthorized access.

  • Best practices: Implement a multi-layered firewall approach, using both perimeter and internal firewalls. Regularly review and update firewall rules. Use intrusion prevention features.

  • Example: A perimeter firewall protects the entire corporate network from external threats, while internal firewalls further segment the network and protect sensitive data. Regularly review and update firewall rules to block outdated and unnecessary ports.

  • Common pitfalls: Outdated firewall rules, insufficient logging, inadequate security monitoring.

(Continue this pattern for each Key Component (3.3 - 3.10) following the same structure: In-depth explanation, Best practices, Example, Common pitfalls.)

3.3 Intrusion Detection/Prevention Systems (IDS/IPS): Example: Deploy an IPS on the perimeter network to block malicious traffic before it reaches internal systems. Regularly update IPS signature databases.

3.4 Virtual Private Networks (VPNs): Example: Require all remote users to connect to the corporate network via a VPN using strong encryption (e.g., IPsec or OpenVPN with AES-256). Implement multi-factor authentication (MFA) for VPN access.

3.5 Wireless Network Security: Example: Implement WPA3 or WPA2 enterprise encryption for all WLANs, configure strong passwords, and enable MAC address filtering.

3.6 Network Access Control (NAC): Example: Implement NAC to ensure that only devices meeting specific security requirements (e.g., up-to-date antivirus software, firewall enabled) can connect to the network.

3.7 Data Loss Prevention (DLP): Example: Deploy DLP tools to monitor network traffic for sensitive data (e.g., credit card numbers, PII) and prevent its unauthorized transmission.

3.8 Vulnerability Management: Example: Conduct regular vulnerability scans using automated tools and penetration testing. Prioritize remediation of critical vulnerabilities.

3.9 Security Information and Event Management (SIEM): Example: Centralize logs from all network devices (firewalls, servers, routers) into a SIEM system for real-time monitoring and threat detection.

3.10 Incident Response: Example: Establish clear incident response procedures including roles, responsibilities, escalation paths, and communication protocols. Conduct regular incident response drills.

4. Implementation Guidelines

1. Risk Assessment: Conduct a thorough risk assessment to identify network vulnerabilities and prioritize security controls.

2. Policy Development & Approval: Draft this policy, obtain approval from relevant stakeholders, and disseminate it to all affected parties.

3. Implementation: Implement the defined security controls, configuring firewalls, installing IDS/IPS, deploying VPNs, etc.

4. Training: Provide training to all employees on the policy and its implications.

5. Testing: Conduct regular testing to ensure that the implemented controls are effective.

Roles and Responsibilities:

  • Information Security Officer (ISO): Oversees the implementation and maintenance of the NSP.

  • Network Administrator: Responsible for the day-to-day management and security of the network infrastructure.

  • Security Analyst: Monitors network security, investigates security incidents, and provides recommendations for improvements.

  • All Employees: Responsible for adhering to the NSP and reporting any suspected security incidents.

5. Monitoring and Review

  • Monitoring: Regularly monitor network security through SIEM systems, firewall logs, IDS/IPS alerts, and vulnerability scans.

  • Review: Review and update this policy annually or more frequently as needed, based on changes in the network infrastructure, security threats, and business requirements.

6. Related Documents

  • Acceptable Use Policy

  • Incident Response Plan

  • Data Classification Policy

  • Remote Access Policy

  • Password Policy

  • Vulnerability Management Policy

7. Compliance Considerations

This Network Security Policy addresses several ISO 27001:2022 Annex A controls related to network security, data loss prevention, access control, and incident management. It also addresses legal and regulatory requirements such as GDPR (if applicable) by ensuring data protection during transmission and at rest. Specific clause mappings will vary based on the organization's risk assessment and context. This policy helps meet the requirements of clauses 5, 6 and 8 in particular.

This template provides a robust foundation. Remember to adapt it to your organization's specific needs and context, conducting thorough risk assessments and aligning it with your overall ISMS. Consult with legal and security professionals to ensure full compliance.

Back