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.