My 2 cents (read rants) on Information security
My 2 cents (read rants) on Information security

AWS Lambda Security Threats and Mitigations

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Amazon Web Services (AWS) Lambda is a popular serverless computing platform that allows users to run code without the need to manage infrastructure. While it offers many benefits, like scalability and low costs, it also comes with some potential security threats that you should be aware of and take steps to mitigate.

Security is important to AWS Lambda for several reasons. First, Lambda functions often process sensitive data, such as customer information, financial records, and personal data. If this data were to be accessed or modified by unauthorized parties, it could result in serious harm to individuals and businesses. Therefore, it’s important to ensure that your Lambda functions are protected from potential security threats.

Second, Lambda functions can be used to build critical applications and services that are relied upon by many users. If a security incident were to compromise your Lambda functions, it could result in widespread disruption and damage to your business and reputation. Therefore, it’s important to take steps to prevent and mitigate potential security threats.

Third, AWS Lambda is a shared service that is used by many customers. If a security incident were to affect one customer’s Lambda functions, it could potentially affect other customers as well. Therefore, AWS and its customers have a shared responsibility to ensure the security of the Lambda platform.

Potential Threats to AWS Lambda

Here are some examples of potential threat scenarios to AWS Lambda:

  1. An attacker obtains your AWS access keys and uses them to gain unauthorized access to your Lambda functions and the data they process.
  2. An attacker uploads or modifies your Lambda functions to inject malicious code that can be used to steal data, compromise other systems, or take over your entire AWS account.
  3. An attacker launches a distributed denial of service (DDoS) attack against your Lambda functions, overwhelming them with a large number of requests and causing them to crash or become unresponsive.
  4. An attacker exploits a vulnerability in your Lambda functions or the underlying infrastructure to gain access to your systems or data.
  5. An attacker uses social engineering tactics to trick one of your employees into giving them access to your Lambda functions or AWS account.

These are just some examples of potential threat scenarios to AWS Lambda which you can get by doing Threat Modelling for your Lambda deployment and functions. It’s important to be aware of the risks and take steps to prevent and mitigate them. You can refer to the AWS Lambda documentation and the AWS Security Blog for more information on how to protect your serverless applications from these and other threats.

How to Secure AWS Lambda

Here are some steps you can take to mitigate these and other threats to AWS Lambda:

  1. Use strong and unique access keys for your AWS account and regularly rotate them to prevent unauthorized access.
  2. Implement multi-factor authentication for your AWS account to add an extra layer of security.
  3. Use version control for your Lambda functions and carefully control who has access to modify them.
  4. Regularly review your Lambda functions for any suspicious changes or code injections.
  5. Use AWS’s built-in DDoS protection, as well as third-party tools and services, to monitor and defend against DDoS attacks.
  6. Use Amazon GuardDuty, a threat detection service, to monitor for any potential security threats to your Lambda functions.
  7. Follow AWS’s security best practices, including the AWS Lambda Security Best Practices guide, to help ensure the security of your serverless applications.

Secure Lambda function example template

Securing both your AWS Lambda functions and their deployment is important because they are both critical components of your serverless application. If your Lambda functions are not secure, they can be exposed to a variety of security risks, such as unauthorized access, malicious code injection, and data breaches. These risks can compromise the confidentiality, integrity, and availability of your data and systems, and can have serious consequences for your business and your customers.

The below code creates an AWS Lambda function that is designed to be secure against common threats and vulnerabilities.

const AWS = require('aws-sdk');
const lambda = new AWS.Lambda({
  region: 'us-east-1'

exports.handler = (event, context, callback) => {
  // Ensure that the request is using HTTPS
  if (event.headers['X-Forwarded-Proto'] !== 'https') {
    callback(null, {
      statusCode: 301,
      headers: {
        'Location': 'https://' + event.headers.Host + event.requestContext.path
      body: ''

  // Verify that the request is coming from a trusted source
  const signature = event.headers['X-Slack-Signature'];
  if (!signature) {
    callback('Missing X-Slack-Signature header');

  const timestamp = event.headers['X-Slack-Request-Timestamp'];
  if (!timestamp) {
    callback('Missing X-Slack-Request-Timestamp header');

  // Validate the request signature using a shared secret
  const hmac = crypto.createHmac('sha256', process.env.SLACK_SIGNING_SECRET);
  hmac.update(timestamp + '.' + event.body);
  const expectedSignature = 'v0=' + hmac.digest('hex');
  if (signature !== expectedSignature) {
    callback('Invalid X-Slack-Signature header');

  // Process the request and respond
  // ...

The function first checks that the incoming request is using HTTPS, which is a secure protocol for transmitting data over the web. If the request is not using HTTPS, the function redirects the request to the HTTPS version of the same URL.

Next, the function verifies that the request is coming from a trusted source by checking for a valid X-Slack-Signature header. This header is added by Slack to requests that are sent to your Lambda function, and it contains a digital signature that is generated using a shared secret known only to you and Slack.

If the X-Slack-Signature header is missing or invalid, the function returns an error and does not process the request. Otherwise, the function proceeds to validate the request signature using the shared secret and the X-Slack-Request-Timestamp header, which contains the timestamp of the request.

If the signature is valid, the function can continue processing the request and responding to it. The specific processing and response depend on the specific logic and functionality of your Lambda function.

Overall, this code provides a basic example of how to secure an AWS Lambda function against common threats and vulnerabilities, such as unauthorized access and malicious code injection. It uses HTTPS for secure communication and digital signatures for authentication, which can help protect the integrity and confidentiality of your Lambda functions and data.

AWS Lambda Security Resources

Here are some links to resources that provide guidance on how to secure your AWS Lambda deployments:

These resources provide detailed information on how to properly manage access keys, implement multi-factor authentication, use version control, and follow other best practices for securing your AWS Lambda deployments.

By taking these steps, you can help protect your AWS Lambda functions from potential security threats and keep your data and systems safe. For more information, you can refer to the AWS Lambda documentation and the AWS Security Blog.

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