CYB-DOC-01-1 Network Security Policy

Implementation guidance

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Purpose of this document

This document describes the organisation’s policy regarding how computer networks will be secured and managed.

Areas of Cyber Essentials addressed

The following areas of the Cyber Essentials scheme are addressed by this document:

• Control 1: Firewalls

• Control 2: Secure Configuration

General guidance

This document is intended to document the principles used in designing and implementing the security of your network. There are many ways of constructing networks and you will need to tailor this policy to represent how yours is structured to provide security for your organisation. As this is a policy, the level of detail should not be too specific, but the policy may be supported by lower-level documentation such as network diagrams and procedures.

Review frequency

Due to the rate of change of technology, we would suggest this document is reviewed at least annually and ideally every six months.

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Network Security Policy

DOCUMENT REF

CYB-DOC-01-1

VERSION 1

DATED [Insert date]

DOCUMENT AUTHOR [Insert name]

DOCUMENT OWNER [Insert name/role]

Revision history

Approval

1 Introduction

The use of networks is an essential part of the day-to-day business of [Organization Name]. Networks not only connect many business processes together internally, but they also link the organisation with its suppliers, customers, stakeholders and the outside world.

The organisation’s networks have evolved to become the circulatory system of the company, transporting information to where it needs to go and enabling business to be carried out effectively. But the fact that so much information runs through our networks makes them a target for those who would try to steal that information and disrupt our business. Therefore, these networks need to be protected to ensure that the security of our vital information is assured.

The effective protection of our networks requires that we adopt good practices in information security covering the design, implementation, operation and management of them, and that we ensure everyone involved follows these practices. This policy sets out [Organization Name]’s rules and standards for network protection and acts as a guide for those who create and maintain our IT infrastructure. Note that this policy does not apply to network equipment provided by employees themselves when working from home.

This control applies to all systems, people and processes that constitute the organisation’s information systems, including board members, directors, employees, suppliers and other third parties who have access to [Organization Name] systems.

The following policies and procedures are relevant to this document:

• Mobile Device Policy

• Software Policy

• Anti-Malware Policy

• Password Policy

• Remote Working Policy

• Acceptable Use Policy

• Firewall Rule Change Process

2 Network Security Policy

At all connection points between the internal network and an insecure external network (such as the Internet) effective measures, such as a firewall, must be put in place to ensure that only authorised network traffic is allowed.

Where possible, multiple layers of protection will be used to ensure that the failure of a single device does not expose the network to attack. For example, network firewalls (for example on a router) will be supplemented by host-based software firewalls on servers and client computers in order to provide several levels of firewall protection.

Servers that are intended to be accessed from the Internet (such as web servers) must be connected to a separate area of the firewall (referred to as a De-Militarised Zone, or DMZ) in order to provide additional protection for the internal network.

Where information is to be transferred over a public network such as the Internet, strong encryption techniques must be used to ensure the security of the data transmitted.

Access to wireless networks must be secured using a strong password. A guest wireless network may be provided for visitors. This must be physically separate from all internal networks (including internal wireless networks) and secured using a firewall.

The ability to connect devices to a wireless network using the WPS (Wi-Fi Protected Setup) button on the access point or router itself must be disabled.

Wireless access point admin logon passwords must always be changed from the default to a strong password.

Network equipment in remote offices will be housed in secure cabinets, which must be locked at all times.

Wireless access points located in public areas must be hidden from view where possible and must be placed in positions where access by the public is difficult, for example in or near the ceiling. A lockable protective casing must be installed where an access point is located in an unprotected public area, such as a car park.

Where there is a requirement for remote access across the Internet to the internal network (for example by homeworkers), a Virtual Private Network (VPN) will be used. In such cases multi-factor authentication (MFA, for example using a phone app or via a text message) is a prerequisite so that knowledge of a password on its own is not enough to gain access. Remote access must be granted on an “as required” basis rather than for all users by default.

Admin passwords to network devices must be changed on installation of the device to a strong password of at least eight characters if additional controls such as MFA or common password blocking is used, or twelve characters if a password is used on its own Passwords must be changed in the event that they are compromised, or there is a reasonable suspicion that this is the case. Access to router and firewall settings across the Internet must be

restricted to defined IP addresses, or using MFA, or where available, both. Such access must be supported by a documented business case which is approved by management.

Where possible, a single supplier policy will be used for network hardware. An exception will be made where the use of multiple vendor hardware may increase the level of security provided, such as by using two different firewalls.

Network routing will be based on [Insert manufacturer, for example, Cisco] routers. [Insert manufacturer, for example, Cisco] Gigabit switches will be used as standard for connecting devices to the network. Switch ports will be configured to be disabled until required. More basic network devices, such as hubs, will not be used due to their inherent security weaknesses.

The network protocol IPv4 (Internet Protocol Version 4) will be used on internal networks. However, new network devices purchased must support IPv6 (Internet Protocol Version 6, its successor) in preparation for the future.

The internal network address range used will be 192.168.0.0 – 192.168.254.254. IP addresses and associated network information for desktop and laptop computers will be automatically assigned using a DHCP (Dynamic Host Configuration Protocol) server.

Only network protocols and ports that are explicitly required on a specific server will be enabled by default in order to reduce the attack surface. These must be supported by a documented business case which is approved by management and reviewed on regular basis. This is especially true for servers within the DMZ of the firewall(s).

3 Conclusion

Network security is a cornerstone of [Organization Name]’s defences against many of the threats with which we are faced. Only by designing effective security into every new system and network from the beginning can effective control be maintained, and risk reduced.

Combined with watchful monitoring of the network itself and the tools put in place to manage it, this should ensure that the number and severity of network security incidents is minimised and our exposure from those that do occur is not as great as it otherwise might have been.