Securing Cloud Migrations: Challenges and Best Practices for AWS and Azure

Migrating to the cloud—particularly AWS and Azure—offers massive scalability and flexibility, but it also introduces new security complexities. The legacy security controls built for traditional on-premises environments don’t translate directly to software-defined, API-driven public clouds. As organizations shift workloads into the cloud, they must rethink their security strategies to address the dynamic nature of AWS and Azure infrastructures.

What is Cloud Migration Security in AWS and Azure?

Whether lifting and shifting a Windows Server VM to an EC2 instance in AWS or replatforming to Azure App Services, security must evolve with your architecture. Cloud migration security refers to the policies, technologies, and processes used to protect data, identities, workloads, and infrastructure throughout the migration process.

Teams must understand the differences in control models between on-prem and cloud—especially the shared responsibility models used by AWS and Azure. In both platforms:

• The cloud provider (AWS/Azure) secures the core infrastructure: physical data centers, networking, hardware, and base services.
• The customer is responsible for workloads, configurations, IAM, and data protection.

Key Security Questions to Address Before Migrating

1. Are we rehosting (lift-and-shift), replatforming, or refactoring for cloud-native services like Lambda (AWS) or Azure Functions?
2. What compliance frameworks (e.g., PCI-DSS, HIPAA, SOC 2) must we align with?
3. Will we use traditional VMs (e.g., EC2 or Azure VMs), or adopt container services like EKS/AKS?
4. How will we implement encryption (S3/KMS vs. Azure Key Vault)?
5. What identity and access strategy (IAM vs. RBAC) will we enforce?

Security teams should conduct threat modeling aligned with the specific AWS or Azure architecture, factoring in cloud-native components, APIs, and evolving attack surfaces.

Why Security Must Be a Priority

Failing to secure migrations can expose sensitive systems to data breaches, downtime, and regulatory fines. Here's why security is essential:

• Data Protection: Use TLS for data in transit and native encryption (e.g., AWS KMS or Azure SSE) for data at rest.
• Regulatory Compliance: Leverage AWS Artifact and Azure Compliance Manager to align cloud configurations with required standards.
• IAM: Enforce MFA, least privilege access, and federation with services like AWS IAM Identity Center or Azure AD Conditional Access.
• Monitoring & Visibility: Enable AWS CloudTrail, AWS Config, and Azure Monitor + Defender for Cloud to maintain full auditability.
• Governance & Inventory: Avoid shadow IT by tagging resources and using tools like Azure Policy and AWS Organizations.

Top Security Challenges During AWS & Azure Migrations

• Skill Gaps: Teams unfamiliar with IAM, networking, and cloud-native services may misconfigure critical controls.
• Data Exposure: Misconfigured S3 buckets or Azure Blobs are a common attack vector.
• IAM Complexity: Managing Azure RBAC roles and AWS IAM policies across services can be overwhelming.
• Misconfigurations: Exposed management ports, open NSGs/Security Groups, or disabled logging can create exploitable gaps.
• Limited Visibility: Lack of unified monitoring across multi-account/multi-subscription environments can blind teams to active threats.

Best Practices for Secure Migrations to AWS and Azure

1. Build a Cloud Governance Model

Include stakeholders from:

• DevOps and Cloud Engineering: Use IaC with tools like AWS CloudFormation, Terraform, or Azure Bicep.
• IAM Specialists: Manage Azure AD integration or AWS IAM roles and policies.
• Security: Implement shift-left testing in CI/CD pipelines, enforce policy-as-code (OPA, Azure Policy), and scan images.
• Compliance and Audit: Ensure mapping to NIST, CIS benchmarks, etc.

Form a Cloud Governance Committee to coordinate strategy and approvals across business, legal, and tech teams.

2. Establish Security Standards

• Use CIS Benchmarks for AWS and Azure to define control plane settings.
• Secure IaC templates before deployment.
• Align DevOps pipelines with security gates.

3. Enforce MFA and Role-Based Access

Use Azure AD MFA or AWS IAM MFA for all root/admin access. Assign roles through RBAC (Azure) or IAM policies (AWS) with least privilege principles.

4. Enable Logging and Monitoring

• Enable AWS CloudTrail, VPC Flow Logs, and Config.
• Use Azure Monitor, Defender for Cloud, and Activity Logs.
• Aggregate logs in CloudWatch Logs, Log Analytics, or a SIEM for centralized analysis.

5. Use CSPM and Security Automation

Adopt tools like:

• AWS Security Hub, GuardDuty, and Inspector
• Microsoft Defender for Cloud, Purview, and Sentinel These tools help continuously monitor posture, detect misconfigurations, and auto-remediate issues at scale.

Cloud vs. On-Prem Security: Three Major Differences

1. Shared Responsibility

Cloud forces organizations to rethink control boundaries. AWS and Azure will secure the infrastructure, but you must secure your workloads, configurations, and data.

2. Everything Is Software

Security is now code-driven. Firewalls, IAM, networking, and even compliance enforcement are all defined in YAML, JSON, or policy-as-code tools.

3. Agile Governance

Decisions must be made fast and by cross-functional teams. Cloud governance requires agility, automation, and real-time collaboration—not rigid, waterfall-era processes.

Securing a cloud migration in AWS or Azure isn’t just about protecting what you’re moving—it’s about reshaping your security model to match the fluid, software-defined nature of the cloud. By building a strong governance framework, enforcing IAM discipline, leveraging native monitoring tools, and embedding security in DevOps pipelines, organizations can reduce risk and set themselves up for secure, compliant success in the cloud.