Secure Serverless Applications in AWS Lambda

Best Practices to Secure Serverless Applications in AWS Lambda

The emergence of serverless computing has transformed the application development and deployment landscape, with AWS Lambda standing out as a top serverless platform. Nevertheless, as more organizations embrace serverless architectures, it’s important to address the security concerns that come with this new approach. This complete guide will examine several security best practices to secure serverless applications in AWS Lambda, equipping you to secure your infrastructure, data, and application.

1. Apply the Principle of Least Privilege

It is important to apply the Principle of Least Privilege when designing serverless functions in order to enhance security. This principle advises granting only the necessary permissions for a task and leveraging AWS Identity and Access Management (IAM) roles to restrict unnecessary privileges. By doing so, the attack surface is limited and the potential impact of a compromised function is reduced.1

2. Utilize Environment Variables for Sensitive Data

To prevent sensitive information such as API keys, database credentials, and encryption keys from being exposed, it is recommended to utilize environment variables. AWS Lambda provides the option to define environment variables that can be encrypted using AWS Key Management Service (KMS), ensuring that sensitive data remains protected and separate from the codebase.

3. Enable AWS Lambda Function VPC Access

In some cases, it may be necessary for a serverless application to access resources within a Virtual Private Cloud (VPC), such as connecting to databases or private subnets. In such cases, it is important to configure the function to run within the desired VPC, enabling secure access to resources while benefiting from the inherent security provided by VPC networking features.

4. Implement Function Input Validation

Input validation is a crucial security practice that prevents common vulnerabilities such as injection attacks. Serverless functions should validate and sanitize all user input to prevent malicious data from compromising the application. Robust input validation can prevent potential security breaches and protect the integrity of the serverless application.2

5. Enable AWS Lambda Function Logging and Monitoring

Logging and monitoring are essential components of a comprehensive security strategy for serverless applications. Enabling AWS CloudWatch Logs for Lambda functions enables the capture of detailed execution logs to investigate security incidents effectively. Additionally, configuring CloudWatch Alarms helps to receive notifications for specific events or performance metrics that might indicate a security breach or abnormal behavior.3

6. Implement Function-Level Encryption

Implementing function-level encryption by encrypting environment variables and function code provides an extra layer of security, safeguarding against unauthorized access and tampering, even in the event of a compromise at the infrastructure or storage level.4

7. Regularly Update Dependencies and Libraries

To ensure the security of serverless applications, it is important to regularly update dependencies and libraries, as outdated components can introduce security vulnerabilities. Establishing a proactive approach to dependency management by regularly monitoring for security patches and updates can help to maintain a secure version of the application.

8. Perform Regular Security Audits

Regular security audits are vital to maintaining a robust security posture for serverless applications. Utilize AWS services such as AWS CloudTrail, AWS Config, and AWS Security Hub to gain visibility into the environment, track configuration changes, and detect security misconfigurations or non-compliant resources. Automated scanning tools and regular penetration testing can help to identify and remediate vulnerabilities proactively.


In summary, ensuring the security of serverless applications in AWS Lambda is a complex undertaking that demands a thorough strategy. By adopting the recommended techniques laid out in this guide, you can construct serverless applications with a robust security framework. It’s essential to stay up-to-date with the latest security measures, utilize the ample security features offered by AWS Lambda, and consistently assess and improve your security protocols. With a proactive and conscientious approach, you can deploy serverless applications in AWS Lambda that are both secure and resilient.


  1. Gillis, A. S. (2023, September 26). principle of least privilege (POLP). Security. ↩︎
  2. Input Validation – OWASP Cheat Sheet Series. (n.d.). ↩︎
  3. Monitoring and troubleshooting Lambda functions – AWS Lambda. (n.d.). ↩︎
  4. Saraiya, K. (2022, January 12). Encrypting environment variables in AWS Lambda function. Medium. ↩︎