AWS Lambda provides strong default security controls across identity, network, data, and operational layers. When combined with least-privilege IAM, VPC isolation, encryption, and continuous monitoring, Lambda enables highly secure, serverless workloads with minimal operational overhead.

1. Identity and Access Management (IAM)

Execution Role

• Each Lambda function assumes an IAM execution role at runtime.

• Permissions are granted using least-privilege IAM policies, defining access to AWS services such as Amazon S3, DynamoDB, or CloudWatch.

• Credentials are short-lived and automatically rotated via AWS STS.

Resource-Based Policies

• Lambda supports resource-based policies to allow external services (e.g., API Gateway, EventBridge, S3) to invoke the function.

• Enables cross-account invocation without sharing IAM roles.

Fine-Grained Access Controls

• Conditions such as aws:SourceArn and aws:SourceAccount restrict invocation scope.

• Integration with IAM permission boundaries and SCPs for enterprise governance.

2. Network Security

VPC Integration

• Lambda functions can run inside a VPC, enabling access to private resources.

• Security controls include:

• Security groups (stateful firewall rules)

• Private subnets

• VPC endpoints (PrivateLink) to avoid public internet exposure

Outbound Traffic Control

• Internet access requires a NAT Gateway.

• Egress can be restricted using network ACLs, security groups, or VPC routing controls.

3. Data Protection

Encryption at Rest

• Lambda code packages, environment variables, and layers are encrypted using AWS KMS.

• Supports both AWS-managed keys and customer-managed KMS keys (CMKs).

Encryption in Transit

• All service-to-service communication uses TLS.

• When invoked through API Gateway or ALB, HTTPS is enforced with configurable TLS policies.

Secrets Management

• Sensitive data should be stored in:

• AWS Secrets Manager

• AWS Systems Manager Parameter Store

• Avoids hardcoding secrets in function code or environment variables.

4. Application-Level Security

Environment Isolation

• Each Lambda invocation runs in an isolated execution environment, preventing cross-function interference.

• The underlying infrastructure is fully managed and patched by AWS.

Concurrency Controls

• Reserved concurrency limits protect backend systems from traffic spikes.

• Prevents denial-of-service scenarios caused by runaway invocation scaling.

Code Integrity

• Function deployment packages are immutable once published.

• Versioning and aliases enable controlled, auditable deployments.

5. Monitoring, Logging, and Threat Detection

Logging and Auditing

• Amazon CloudWatch Logs capture function output and execution details.

• AWS CloudTrail records API-level changes (create, update, delete, invoke).

Threat Detection

• Amazon GuardDuty identifies anomalous or malicious behavior related to Lambda activity.

• AWS Config evaluates compliance against security baselines.

Operational Visibility

• Metrics such as invocation count, errors, throttles, and duration support security monitoring and incident response.

6. Supply Chain and Deployment Security

Code Signing

• AWS Lambda code signing ensures only trusted artifacts are deployed.

• Integrates with AWS Signer to enforce deployment integrity controls.

CI/CD Integration

• Supports secure pipelines using AWS CodePipeline, CodeBuild, or third-party tools.

• Enforces separation of duties between build, sign, and deploy stages.

7. Compliance and Governance

Shared Responsibility Model

• AWS secures the underlying infrastructure.

• Customers secure:

• Function code

• IAM permissions

• Network configuration

• Data handling logic

Compliance Support

• Lambda is compliant with major frameworks (e.g., ISO 27001, SOC, PCI DSS, HIPAA), enabling regulated workloads when correctly configured.