How to Secure Applications During Modernization on AWS

Why Do We Need to Secure Our Applications?  

Cloud environments are very dynamic and interconnected. A single misconfiguration or exposed API key can lead to:  

• Data breaches 

• Compliance violations 

• Costly downtime 

Attackers often target application-level weaknesses, not just infrastructure gaps. If any application handles sensitive data, financial transactions, or user credentials, security is critical. 

Common Mistakes Made When Building Applications

• Hardcoding API keys and credentials 

• Ignoring dependency vulnerabilities 

• Skipping encryption/decryption for sensitive data 

Essential Security Best Practices

1. Identity and Access Management (IAM)

• Create dedicated IAM roles for your Lambda functions, EC2 instances, or ECS tasks instead of hardcoding access keys in your application. 

• We must regularly review who has permissions using the IAM Access Analyzer. 

• We must avoid using the root account for day-to-day operations/ any operations as a developer. 

2. Don’t Store/Share Secrets in Your Code

Your appsettings.json is not the right place for secret keys. Storing API keys or database passwords. 

• We must use AWS Secrets Manager or Parameter Store to keep secrets safe. 

• Fetch keys at runtime by using AWS SDK for .NET or the AWSSDK.Extensions.NETCore.Setup configuration provider 

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3. Always Encrypt Data 

Encryption is one of the best practices to encrypt our sensitive data 

• Enable HTTPS by default for all your endpoints.  
• Use AWS Certificate Manager (ACM) to issue and manage SSL/TLS certificates. 
• In your application, make sure that all traffic is redirected to HTTPS by adding app.UseHttpsRedirection(); 
• AWS KMS to encrypt your S3 buckets, RDS databases, and EBS volumes.
• If you’re using SQL Server on RDS, enable Transparent Data Encryption (TDE). 

 Encrypt & Decrypt API Key with KMS 

4. Build a Secure Network Foundation

• Must use VPCs with private subnets for backend services. 

• Control the traffic with Security Groups and Network ACLs. 

• Use VPC Endpoints to keep traffic within AWS’s private network  

• Use AWS WAF to protect your APIs, and enable AWS Shield to guard against DDoS attacks. 

5. Keep Your Code and Dependencies Clean

Even the best infrastructure can’t save a vulnerable codebase. 

• Update your .NET SDK and NuGet packages regularly. 

• Use Amazon Inspector for runtime and AWS environment security, and tools like Dependabot for Development-time dependency security to find vulnerabilities early. 

• Add code review analysis tools (like SonarQube) in your CI/CD pipeline. 

6. Log Everything and Watch

• Enable Amazon AWS CloudWatch for all central logging and use AWS X-Ray to trace requests through the application. 

• Turn on CloudTrail to track every API call across your account. 

• Enable GuardDuty for continuous threat detection.