7.1 Cloud Infrastructure Security
7.1.1 Foundational Infrastructure Security Techniques
- Secure Architecture: Design with security as a principle—segregate resources, least privilege access, secure storage, communications, and configurations.
- Secure Deployment & Configuration: Harden all components (VMs, containers, storage, networking) using security benchmarks (e.g., CIS benchmarks).
- Continuous Monitoring & Guardrails: Use preventative/reactive controls (e.g., AWS Config rules, Azure Policies) to enforce security policies and auto-remediate violations. Enable logging and monitoring across all components.
7.1.2 CSP Infrastructure Security Responsibilities
- Facilities: Physical security (access control, surveillance).
- Employees: Screening, training, and management.
- Physical Network, Storage, Compute: Securing hardware.
- Virtualisation Layers: Securing hypervisors and containers.
- Management Plane: Securing web interfaces and APIs.
- PaaS/SaaS Services: CSP handles underlying infrastructure security under the shared responsibility model.
7.1.3 Infrastructure Resilience
- Single-region resiliency: Basic fault tolerance using auto-scaling, load balancing, backup/recovery.
- Multi-region resiliency: Deploy across multiple regions for higher fault tolerance (higher cost, complexity).
- Multi-provider resiliency: Use multiple cloud providers for critical applications (most complex and costly). Containerisation helps but challenges remain.
7.2 Cloud Network Fundamentals
7.2.1 Software-Defined Networks (SDN)
- SDN separates control plane (routing, network definitions) from data plane (traffic movement).
- Enables dynamic, programmatic network management.
- Customers define logical groupings; providers configure components.
Common SDN-Based Components
- Virtual Networks/VPCs: Logical isolation, control over topology and IP ranges.
- Subnets: Segmentation, security policies, NAT for private subnets.
- Route Tables: Direct traffic, custom routing.
- Network Security Groups: Virtual firewalls, granular security, micro-segmentation.
- ACLs: Stateless controls at subnet/network level.
- Load Balancer Service: Distributes traffic, enables redundancy, supports WAF/DDOS protection.
- Internet Gateways: Entry/exit for internet traffic.
- Endpoints: Private endpoints for secure, internal access to services.
7.2.2 Cloud Connectivity
- Resources (management plane, workloads, storage, APIs) can be exposed to the internet.
- Private networking options (VPNs, third-party services) connect cloud to data centres.
- Security risks arise from misconfigured boundaries; controlling traffic flows is critical.
7.3 Cloud Network Security & Secure Architectures
7.3.1 Preventative Security Measures
- CSP Firewalls: Built-in, easy to manage, but less customisable.
- Virtual Appliances: Flexible, high availability, but complex and maintenance-heavy.
- Web Application Firewalls (WAFs): Protect against OWASP Top 10 vulnerabilities.
7.3.2 Detective Security Measures
- Flow Logs & DNS Logs: Monitor traffic patterns, detect anomalies, identify breaches and exfiltration. Handling logs at scale is challenging.
7.4 Infrastructure as Code (IaC)
- IaC uses machine-readable configuration files to manage infrastructure.
- Key concepts:
- Architectures described by code
- Deployment via management plane API
- CI/CD pipelines for automation
- Security scanning in pipelines
- Version control and change tracking
- Benefits:
- Automated compliance checks
- Consistent security posture
- Rapid rollback for fixes
- IaC is often mandated for reproducibility and security.
7.5 Zero Trust for Cloud Infrastructure & Networks
7.5.1 Software-Defined Perimeter (SDP) & Zero Trust Network Access (ZTNA)
- SDP: Creates a “dark” network, invisible to unauthorised users. Requires authentication and authorisation, uses identity-centric controls and micro-segmentation.
- ZTNA: Replaces VPNs with granular, application-specific access. Authorises users based on identity, device, location, and context. Can be cloud-hosted or on-premises.
7.6 Secure Access Service Edge (SASE)
- SASE combines network security functions with WAN and proxy capabilities for cloud-native security.
- Moves security filtering to the edge (near user devices) using endpoint agents and global points of presence.
- Avoids inefficient routing (“backhauling”) and supports Zero Trust Architecture.
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