Why Your Cloud Migration Security Plan Is Probably Wrong

53%. That's the percentage of organizations that say security and compliance is their top scaling challenge when running AI workloads, according to Flexera's 2026 State of the Cloud report. But here's the thing: that number isn't just about AI. It's a symptom of a deeper problem that plagues every cloud migration, AI or not. We think we understand cloud security because we've been doing 'security' on-premises for decades. But the cloud flips the model on its head. It's not about buying a bigger firewall; it's about understanding who's responsible for what, and then actually doing your part.

Isn't the cloud provider responsible for security?

This is the single most dangerous misconception in cloud migration. The cloud provider is responsible for the security of the cloud, but you are responsible for security in the cloud. Both AWS and Microsoft hammer this point home. Under the AWS shared responsibility model, AWS protects the hardware, software, networking, and facilities that run their services. But if you're using Amazon EC2, you're on the hook for the guest operating system, security patches, and the security group firewall. Move to something like Amazon S3, and AWS manages the infrastructure, but you still own your data, encryption choices, and IAM permissions. Microsoft's Azure model is equally clear: you always own your data classification, protection, and access management. So when you hear a vendor claim they've got security covered, remember: they're talking about their part, not yours.

Is 'lift and shift' really a security risk?

Yes, but not for the reasons you might think. Rehosting, or lift and shift, moves applications as-is, with no code changes. It's fast and simple, but it doesn't automatically make you secure. In fact, rehosting without modification can lead to higher long-term costs because you're running applications in the cloud without cloud-native capabilities. And here's a subtle trap: you might be tempted to skip security assessments because you're not changing anything. But the cloud is a shared environment, and your old on-premises assumptions—like network perimeter controls—don't apply. Take the time to re-evaluate your security posture, even if you're just moving VMs. Don't let the speed of lift and shift lull you into complacency.

Do I really need to worry about compliance in the cloud?

Absolutely. Compliance is not optional, and it's not the cloud provider's job. If you're in a regulated industry, you know the drill. But even if you're not, there are data residency and privacy laws that can bite you. AWS's Retain strategy is specifically for applications that must stay on-premises for compliance reasons, like data residency. And when you do migrate, you might need to split a database so some tables stay on-premises while others move, just to satisfy compliance requirements. That's not a hypothetical—AWS explicitly calls out this scenario. So before you migrate, map your compliance requirements to your cloud architecture. It's a lot easier to plan for this upfront than to retrofit it later.

How do I secure my data during migration?

This is where the rubber meets the road. The most secure path is a private, dedicated connection. Microsoft's Azure Cloud Adoption Framework lists four data migration paths, and they're not all equal. ExpressRoute is a private, dedicated connection that's faster and more secure than the public internet. VPN is an encrypted tunnel over the internet—decent, but not as secure. Azure Data Box is a physical device you ship for offline migration of large data volumes, which is actually a great option if you're moving terabytes. And then there's the public internet, which Microsoft explicitly calls out as the least secure option. My recommendation? If you're moving anything sensitive, shell out for ExpressRoute or a similar private link. It's not just about security; it's about not being the cautionary tale in someone else's blog post.

Can I ever be fully secure in the cloud?

No. And anyone who tells you otherwise is selling something. The cloud is not a magic security bullet. In fact, Flexera's 2026 report found that security and compliance is the top scaling challenge for 53% of organizations running AI workloads. That doesn't mean you should give up—it means you need to be realistic. You need a defense-in-depth strategy that leverages the cloud's native tools. For example, AWS's Well-Architected Framework provides best practices for designing secure workloads, and it's free to use. Microsoft's Azure Well-Architected Framework has a similar set of pillars. And don't forget about automation: infrastructure as code (IaC) lets you define your security controls in code, version them, and test them. That's a huge step up from manual configurations. But even with all that, you'll never be 100% secure. The goal is to be secure enough to pass audits, protect your customers, and sleep at night.

Quick tip or warning

Warning: Don't assume that because you're using a managed service, you're off the hook. Even with abstracted services like S3, you still own your data and access permissions. Get that wrong, and you'll be the next data breach headline.

Bottom line

The single best move you can make for cloud migration security is to explicitly map out the shared responsibility model for each service you plan to use, and then document who owns every security control. Do it before you migrate, not after. That one exercise will save you from the most common and costly mistakes.

Sources

• Flexera 2026 - https://www.flexera.com/blog/finops/the-new-era-of-cloud-what-2026-data-tells-us-about-spend-scale-and-strategy/
• AWS Shared Responsibility - https://aws.amazon.com/compliance/shared-responsibility-model/
• Microsoft Learn (security) - https://learn.microsoft.com/en-us/azure/security/fundamentals/shared-responsibility
• AWS Prescriptive Guidance - https://docs.aws.amazon.com/prescriptive-guidance/latest/large-migration-guide/migration-strategies.html
• Microsoft CAF - https://learn.microsoft.com/en-us/azure/cloud-adoption-framework/get-started/migrate
• IBM (infrastructure as code) - https://www.ibm.com/think/topics/infrastructure-as-code