Lambda is a computing platform by Amazon Web Services that runs code as a response to events. It is serverless and can automatically manage computing resources that are needed by the event-driven code. In short, it is a high-scale computing platform based on functions.

The events that trigger Lambda into actions are not limited to the ones that occur on AWS but also include events by third-party supportive services. With the help of Lambda, it is now easier to build event-driven and reactive systems. Lambda is so efficient that when there are simultaneous events that trigger action, it just runs the functions parallelly. Lambda scales the computing resources up and down based on each individual event. Therefore, no server or container is left idle. Architectures built using Lambda functions reduce wasted capacity.

FaaS is fast ruling today

Function-as-a-Service (FaaS) event-driven serverless computing systems are growing in popularity and AWS Lambda has become developers’ choice due to its versatile usage of computing resources. FaaS has no containers or servers in the architecture itself thereby allowing vendors to provide free range scalability and reliability of resource allocation. A Lambda function typically consists of the code, the configuration of the code, and event sources. The event sources are responsible for detecting the events as and when they occur and invoke the function. Thus, there can be more than one event that can trigger a Lambda function.

A common example of an event that can trigger a Lambda function is API gateway that receives a HTTPS request.

Security is key

Regardless of designing a serverless architecture, implementing and enabling security best practices in the application must always be a developer’s first priority. The absence of a server in a serverless architecture still leaves the application vulnerable. The typical security implementations include installing malware/antivirus softwares, enabling firewalls, detecting intruders and protection systems, and monitoring the integrity of the files that are being installed. AWS has a set of security best practices that it recommends for Lambda function integration.

The following are security best practices that should be applied on serverless applications:

  • One IAM role per function

Identity and Access Management (IAM) role is a kind of AWS identity that can be used to allocate permission policies about what each identity can do. All Lambda functions need a single relationship with an IAM role. This ensures that even if multiple functions with the same policy are triggered at the same time, all the functions will be granted at the same time.

  • Persisting secrets

Database credentials, encryption keys, and dependency access keys are best kept secrets in a Lambda function. Some options for managing such secrets in the application are as follows:

  • Encryption helpers

Pro: Easy to retrieve the secret as it is provided directly in the function environment, thus minimizing latency.

Con: There is a need for a new function as environment variables are rigid.

Pro: This allows enough flexibility of how Lambda functions and the secrets are related to each other.

Con- A request is a need to retrieve the secret, which means more code needs to be written.

  • How to protect secrets

Secrets are best protected when they aren’t written on disk. Yet another way to protect secrets is by rotating them in case they need to be revoked.

  • API authorization

API gateway allows the developer ownership over authentication and authorization and is a unique form of event source for Lambda function. However, the developers are responsible for ensuring security best practices of the enabling API.

  • VPC security

Amazon Virtual Private Cloud or VPC is a service that is used to launch AWS resources from a virtual network. In case a Lambda function requires access to a VPC resource, the developer needs to keep in mind to enable security best practices through network ACLs, function-specific subnet, security groups, and routing tables that direct the Lambda functions to reach intended destinations.

  • Deployment access control

Removing direct access to APIs of any Lambda functions reduces the possibility of human errors. The Lambda APIs must be treated with extreme care and caution and any code changes must be done through automation.

The key to using a Lambda function is how it can operate very well even without the presence of a server. With the use of right security measures the Lambda function is perfect for minimizing or restricting resources left idle.

Talk to us today to learn more about how efficient and resource-saving your application can actually be.


AWS Lambda is a serverless, high-scale computing platform based on functions. Lambda runs code when triggered by events and is efficient enough to scale computing resources up and down based on each individual event. In this blog, let us see the various security best practices recommended by Amazon Web Services for Lambda implementations.


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