Running workloads across multiple cloud providers has become standard practice for UK businesses seeking resilience, avoiding vendor lock-in, or satisfying regulatory requirements. The security challenge multiplies with each additional provider because every platform implements identity, networking, and access controls differently.
A security team that understands AWS IAM policies intimately may struggle with Azure’s role-based access control model and vice versa. Misconfigurations that would never happen in a team’s primary cloud appear regularly in their secondary environment simply because the concepts do not map one-to-one between providers.
The Shared Responsibility Confusion
Both AWS and Azure operate under shared responsibility models, but the specifics differ. Where each provider draws the line between their responsibilities and yours varies by service type. A team that understands exactly what AWS manages for an RDS instance might incorrectly assume Azure SQL Database works the same way.
Networking presents particular challenges. AWS security groups are stateful and attach to instances. Azure network security groups attach to subnets or network interfaces with different rule evaluation logic. Misconfiguring either one exposes resources to unintended traffic, but the mistakes look different on each platform.
William Fieldhouse, Director of Aardwolf Security Ltd, comments: “Multi-cloud environments suffer from a consistency problem. Organisations build strong security controls in whichever platform they adopted first, then apply the same mental models to the second provider. The gaps appear where the platforms diverge, which is exactly where attackers look. Each cloud environment needs testing by specialists who understand that specific platform’s security model.”
Testing Each Environment Properly
Generic cloud security assessments that apply the same checklist to every provider miss platform-specific weaknesses. Effective AWS penetration testing requires deep knowledge of IAM policy evaluation, S3 bucket policies, Lambda execution roles, and the specific ways AWS services interact.
Similarly, Azure penetration testing demands understanding of Entra ID conditional access, Azure RBAC inheritance through management groups, Key Vault access policies, and Azure-specific attack paths. Different platforms, different expertise, different findings.
Managing Multi-Cloud Security
Centralise visibility across providers using a cloud security posture management (CSPM) tool that supports both platforms. Standardise your security baseline requirements even though the implementation details differ. Define what least privilege means for each provider and enforce it consistently.
Logging and monitoring add further complexity. AWS CloudTrail and Azure Monitor use different schemas, retention policies, and alerting mechanisms. A security event in one environment may not trigger the same detection logic that catches it in the other, leaving blind spots that span the gap between providers.
Build a cross-cloud incident response plan that accounts for the different tools, access methods, and escalation paths each provider requires. A runbook built for AWS will not translate directly to Azure. Invest the time to create provider-specific procedures that your team can execute under pressure without guessing.
Multi-cloud environments deliver genuine business benefits. Realising those benefits without multiplying your security risk requires treating each platform as its own security domain, with dedicated expertise, testing, and ongoing monitoring.