Networks security

ISO 27001:2022 control A.8.20 is a technological control requiring organizations to ensure their networks and network devices are secured, managed, and controlled. These ISO 27001 A.8.20 network security requirements mandate the protection of data in transit and the prevention of unauthorized access to the IT infrastructure.

To satisfy an ISO 27001 network security audit checklist, auditors typically look for an approved network security policy (or Operations Security Policy), updated network architecture diagrams, and evidence of production network segregation (e.g., VPNs, VPC settings, or security groups). They will also request penetration test reports and IDS/IPS alert configurations. Tools like WatchDog Security's Compliance Center can help map each evidence item to A.8.20 and maintain an audit-ready evidence trail with ownership and review dates.

While network segmentation is explicitly covered in A.8.22, A.8.20 generally expects VLAN segmentation and DMZ design for ISO 27001 as part of a secure network architecture. Auditors verify this by reviewing network diagrams, routing tables, and firewall rules to ensure sensitive areas are properly isolated.

Changes to firewall rules must follow a formal change management process, complete with justification and approval tickets. Additionally, the firewall rule review frequency ISO 27001 best practice dictates at least an annual review (or bi-annual for high-risk environments) to identify and remove obsolete or overly permissive rules. WatchDog Security's Policy Management can help document the firewall rule review procedure and track acknowledgements so the process is consistently followed.

Best practices for network device hardening routers switches ISO 27001 include disabling unused ports and services, changing default vendor credentials, enforcing strong encryption for management sessions (SSH/HTTPS instead of Telnet/HTTP), and ensuring firmware is regularly updated through a patch management process.

Yes, implementing an Intrusion Detection System (IDS) or Intrusion Prevention System (IPS) is highly recommended. Auditors look for evidence of monitoring network traffic logs for ISO 27001 evidence, such as screenshots of automated alerts sent to security teams when abnormal activity or potential threats are detected.

Organizations should enforce Role-Based Access Control (RBAC) and Multi-Factor Authentication (MFA) for anyone accessing network device management interfaces. Using an out-of-band management network or a secure jump host (bastion server) further restricts administrative access from the general corporate network.

For cloud and hybrid network security ISO 27001 A.8.20, organizations must logically secure their virtual networks. This involves configuring strict Virtual Private Cloud (VPC) or VNet boundaries, applying least-privilege security groups and network access control lists (NACLs), and securely routing traffic across hybrid environments.

Secure VPN remote access requirements ISO 27001 mandate that all remote connections use strong encryption protocols (like TLS 1.2+ or IPsec). Furthermore, access must require MFA, be limited to an authorized list of users, and be actively logged to detect unauthorized connection attempts.

A.8.20 is the foundational control focused on securing and hardening the network devices and architecture itself. A.8.21 deals specifically with defining and monitoring the security mechanisms of network services provided by third parties or internal teams. A.8.22 specifically requires the logical or physical segregation of different networks, services, or user groups.

Auditors usually want consistent proof of network controls such as firewall rule reviews, change tickets, network diagrams, monitoring/alert outputs, and vulnerability scan results. A GRC platform can centralize these artifacts and map them to A.8.20; for example, WatchDog Security's Compliance Center can help track evidence requests, link artifacts to the control, and flag gaps when expected evidence is missing or out of date.

Network findings often come from misconfigurations, overly permissive rules, unpatched devices, or weak remote access controls, and they need clear ownership and deadlines to reduce exposure. Tools like WatchDog Security's Risk Register can document each network risk, assign treatments (e.g., segmentation, device hardening, firewall cleanup), track due dates, and produce management-ready status reporting aligned to ISO 27001 A.8.20.