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ISO 27001 Annex A 8.23: How Web Filtering Reduces Cyber Risks

There is a risk of malware attacks on corporate networks and information systems if employees visit websites with malicious content.

For example, attackers could send phishing emails to employees’ work emails, enticing them to click on links and visit websites. If an employee visits this website, malware may be automatically uploaded to the employee’s device, enabling infiltration into corporate networks. In this attack, malware is automatically downloaded once the employee accesses a website, referred to as a drive-by download.

Therefore, organisations must implement appropriate web filtering controls to restrict and control access to external websites and prevent security threats.

The Purpose of ISO 27001:2022 Annex A 8.23

The Annex A Control 8.23 of ISO 27001:2022 also assists organisations in eliminating security risks such as malware infection from accessing external websites with malicious content.




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Ownership of Annex A 8.23

The Chief Information Security Officer is responsible for ensuring that appropriate measures are taken for compliance with 8.28, which involves identifying high-risk external websites and designing and implementing appropriate access and web filtering controls.

General Guidance on ISO 27001:2022 Annex A 8.23

To protect employees from accessing external websites that may contain viruses, phishing materials, or other types of illegal information, organisations should establish and implement the required controls.

By blocking the IP address or domain of dangerous external websites, it is possible to prevent access to such websites. The automatic detection of malware can be accomplished by some browsers and anti-malware tools, for example.

Control 8.23 of ISO 27001 Annex A recommends that organisations determine what types of websites employees should not be allowed to access.

Specifically, it is recommended that the following types of websites be blocked:

  • Websites with the capability of uploading information. Obtaining access should be subject to authorisation and only be granted in cases where business reasons are valid.
  • A website that is known or suspected to contain malicious material, such as a website containing malware.
  • Servers are used for command and control.
  • Threat intelligence-identified malicious websites. For more information, organisations should refer to Annex A Control 5.7.
  • Sites that distribute materials and content that are illegal.

Organisations are advised to set up rules for safe and appropriate access to and use online resources before implementing this Annex A Control. Additionally, websites containing inappropriate material should be restricted.

A regular review and update should be conducted.

Supplementary Guidance on Staff Training

Control 8.23 of ISO 27001:2022 specifies that all employees should receive training on safely accessing online resources.

Organisations should conduct this training to ensure employees know their own rules and how to report security concerns.

Further, training should also cover the exception process for accessing restricted websites for legitimate business reasons.

Furthermore, training should cover browser advisory messages that warn users a website isn’t secure but allow them to continue. These warnings must be addressed by staff.

Annex A 8.23 Supplementary Guidance

Among the techniques used for web filtering are:

  • Heuristics.
  • Signatures.
  • List of prohibited and acceptable websites.
  • Domain configuration.



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What Are the Changes and Differences From ISO 27001:2013?

ISO 27001:2022 Annex A 8.23 is a new control not found in the 2013 version of the standard.

Table of All ISO 27001:2022 Annex A Controls

In the table below you’ll find more information on each individual ISO 27001:2022 Annex A Control.

ISO 27001:2022 Organisational Controls
Annex A Control Type ISO/IEC 27001:2022 Annex A Identifier ISO/IEC 27001:2013 Annex A Identifier Annex A Name
Organisational Controls Annex A 5.1 Annex A 5.1.1
Annex A 5.1.2
Policies for Information Security
Organisational Controls Annex A 5.2 Annex A 6.1.1 Information Security Roles and Responsibilities
Organisational Controls Annex A 5.3 Annex A 6.1.2 Segregation of Duties
Organisational Controls Annex A 5.4 Annex A 7.2.1 Management Responsibilities
Organisational Controls Annex A 5.5 Annex A 6.1.3 Contact With Authorities
Organisational Controls Annex A 5.6 Annex A 6.1.4 Contact With Special Interest Groups
Organisational Controls Annex A 5.7 NEW Threat Intelligence
Organisational Controls Annex A 5.8 Annex A 6.1.5
Annex A 14.1.1
Information Security in Project Management
Organisational Controls Annex A 5.9 Annex A 8.1.1
Annex A 8.1.2
Inventory of Information and Other Associated Assets
Organisational Controls Annex A 5.10 Annex A 8.1.3
Annex A 8.2.3
Acceptable Use of Information and Other Associated Assets
Organisational Controls Annex A 5.11 Annex A 8.1.4 Return of Assets
Organisational Controls Annex A 5.12 Annex A 8.2.1 Classification of Information
Organisational Controls Annex A 5.13 Annex A 8.2.2 Labelling of Information
Organisational Controls Annex A 5.14 Annex A 13.2.1
Annex A 13.2.2
Annex A 13.2.3
Information Transfer
Organisational Controls Annex A 5.15 Annex A 9.1.1
Annex A 9.1.2
Access Control
Organisational Controls Annex A 5.16 Annex A 9.2.1 Identity Management
Organisational Controls Annex A 5.17 Annex A 9.2.4
Annex A 9.3.1
Annex A 9.4.3
Authentication Information
Organisational Controls Annex A 5.18 Annex A 9.2.2
Annex A 9.2.5
Annex A 9.2.6
Access Rights
Organisational Controls Annex A 5.19 Annex A 15.1.1 Information Security in Supplier Relationships
Organisational Controls Annex A 5.20 Annex A 15.1.2 Addressing Information Security Within Supplier Agreements
Organisational Controls Annex A 5.21 Annex A 15.1.3 Managing Information Security in the ICT Supply Chain
Organisational Controls Annex A 5.22 Annex A 15.2.1
Annex A 15.2.2
Monitoring, Review and Change Management of Supplier Services
Organisational Controls Annex A 5.23 NEW Information Security for Use of Cloud Services
Organisational Controls Annex A 5.24 Annex A 16.1.1 Information Security Incident Management Planning and Preparation
Organisational Controls Annex A 5.25 Annex A 16.1.4 Assessment and Decision on Information Security Events
Organisational Controls Annex A 5.26 Annex A 16.1.5 Response to Information Security Incidents
Organisational Controls Annex A 5.27 Annex A 16.1.6 Learning From Information Security Incidents
Organisational Controls Annex A 5.28 Annex A 16.1.7 Collection of Evidence
Organisational Controls Annex A 5.29 Annex A 17.1.1
Annex A 17.1.2
Annex A 17.1.3
Information Security During Disruption
Organisational Controls Annex A 5.30 NEW ICT Readiness for Business Continuity
Organisational Controls Annex A 5.31 Annex A 18.1.1
Annex A 18.1.5
Legal, Statutory, Regulatory and Contractual Requirements
Organisational Controls Annex A 5.32 Annex A 18.1.2 Intellectual Property Rights
Organisational Controls Annex A 5.33 Annex A 18.1.3 Protection of Records
Organisational Controls Annex A 5.34 Annex A 18.1.4 Privacy and Protection of PII
Organisational Controls Annex A 5.35 Annex A 18.2.1 Independent Review of Information Security
Organisational Controls Annex A 5.36 Annex A 18.2.2
Annex A 18.2.3
Compliance With Policies, Rules and Standards for Information Security
Organisational Controls Annex A 5.37 Annex A 12.1.1 Documented Operating Procedures
ISO 27001:2022 People Controls
Annex A Control Type ISO/IEC 27001:2022 Annex A Identifier ISO/IEC 27001:2013 Annex A Identifier Annex A Name
People Controls Annex A 6.1 Annex A 7.1.1 Screening
People Controls Annex A 6.2 Annex A 7.1.2 Terms and Conditions of Employment
People Controls Annex A 6.3 Annex A 7.2.2 Information Security Awareness, Education and Training
People Controls Annex A 6.4 Annex A 7.2.3 Disciplinary Process
People Controls Annex A 6.5 Annex A 7.3.1 Responsibilities After Termination or Change of Employment
People Controls Annex A 6.6 Annex A 13.2.4 Confidentiality or Non-Disclosure Agreements
People Controls Annex A 6.7 Annex A 6.2.2 Remote Working
People Controls Annex A 6.8 Annex A 16.1.2
Annex A 16.1.3
Information Security Event Reporting
ISO 27001:2022 Physical Controls
Annex A Control Type ISO/IEC 27001:2022 Annex A Identifier ISO/IEC 27001:2013 Annex A Identifier Annex A Name
Physical Controls Annex A 7.1 Annex A 11.1.1 Physical Security Perimeters
Physical Controls Annex A 7.2 Annex A 11.1.2
Annex A 11.1.6
Physical Entry
Physical Controls Annex A 7.3 Annex A 11.1.3 Securing Offices, Rooms and Facilities
Physical Controls Annex A 7.4 NEW Physical Security Monitoring
Physical Controls Annex A 7.5 Annex A 11.1.4 Protecting Against Physical and Environmental Threats
Physical Controls Annex A 7.6 Annex A 11.1.5 Working In Secure Areas
Physical Controls Annex A 7.7 Annex A 11.2.9 Clear Desk and Clear Screen
Physical Controls Annex A 7.8 Annex A 11.2.1 Equipment Siting and Protection
Physical Controls Annex A 7.9 Annex A 11.2.6 Security of Assets Off-Premises
Physical Controls Annex A 7.10 Annex A 8.3.1
Annex A 8.3.2
Annex A 8.3.3
Annex A 11.2.5
Storage Media
Physical Controls Annex A 7.11 Annex A 11.2.2 Supporting Utilities
Physical Controls Annex A 7.12 Annex A 11.2.3 Cabling Security
Physical Controls Annex A 7.13 Annex A 11.2.4 Equipment Maintenance
Physical Controls Annex A 7.14 Annex A 11.2.7 Secure Disposal or Re-Use of Equipment
ISO 27001:2022 Technological Controls
Annex A Control Type ISO/IEC 27001:2022 Annex A Identifier ISO/IEC 27001:2013 Annex A Identifier Annex A Name
Technological Controls Annex A 8.1 Annex A 6.2.1
Annex A 11.2.8
User Endpoint Devices
Technological Controls Annex A 8.2 Annex A 9.2.3 Privileged Access Rights
Technological Controls Annex A 8.3 Annex A 9.4.1 Information Access Restriction
Technological Controls Annex A 8.4 Annex A 9.4.5 Access to Source Code
Technological Controls Annex A 8.5 Annex A 9.4.2 Secure Authentication
Technological Controls Annex A 8.6 Annex A 12.1.3 Capacity Management
Technological Controls Annex A 8.7 Annex A 12.2.1 Protection Against Malware
Technological Controls Annex A 8.8 Annex A 12.6.1
Annex A 18.2.3
Management of Technical Vulnerabilities
Technological Controls Annex A 8.9 NEW Configuration Management
Technological Controls Annex A 8.10 NEW Information Deletion
Technological Controls Annex A 8.11 NEW Data Masking
Technological Controls Annex A 8.12 NEW Data Leakage Prevention
Technological Controls Annex A 8.13 Annex A 12.3.1 Information Backup
Technological Controls Annex A 8.14 Annex A 17.2.1 Redundancy of Information Processing Facilities
Technological Controls Annex A 8.15 Annex A 12.4.1
Annex A 12.4.2
Annex A 12.4.3
Logging
Technological Controls Annex A 8.16 NEW Monitoring Activities
Technological Controls Annex A 8.17 Annex A 12.4.4 Clock Synchronization
Technological Controls Annex A 8.18 Annex A 9.4.4 Use of Privileged Utility ProgramsAccess Rights
Technological Controls Annex A 8.19 Annex A 12.5.1
Annex A 12.6.2
Installation of Software on Operational Systems
Technological Controls Annex A 8.20 Annex A 13.1.1 Networks Security
Technological Controls Annex A 8.21 Annex A 13.1.2 Security of Network Services
Technological Controls Annex A 8.22 Annex A 13.1.3 Segregation of Networks
Technological Controls Annex A 8.23 NEW Web filtering
Technological Controls Annex A 8.24 Annex A 10.1.1
Annex A 10.1.2
Use of Cryptography
Technological Controls Annex A 8.25 Annex A 14.2.1 Secure Development Life Cycle
Technological Controls Annex A 8.26 Annex A 14.1.2
Annex A 14.1.3
Application Security Requirements
Technological Controls Annex A 8.27 Annex A 14.2.5 Secure System Architecture and Engineering PrinciplesLearning From Information Security Incidents
Technological Controls Annex A 8.28 NEW Secure Coding
Technological Controls Annex A 8.29 Annex A 14.2.8
Annex A 14.2.9
Security Testing in Development and Acceptance
Technological Controls Annex A 8.30 Annex A 14.2.7 Outsourced Development
Technological Controls Annex A 8.31 Annex A 12.1.4
Annex A 14.2.6
Separation of Development, Test and Production Environments
Technological Controls Annex A 8.32 Annex A 12.1.2
Annex A 14.2.2
Annex A 14.2.3
Annex A 14.2.4
Change Management
Technological Controls Annex A 8.33 Annex A 14.3.1 Test Information
Technological Controls Annex A 8.34 Annex A 12.7.1 Protection of Information Systems During Audit Testing

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ISO 27001:2022 Annex A Controls

Organisational Controls