DVA-C02 Practice Test 5 — 10 Questions

Question 1

A developer is building a serverless application using AWS Lambda and Amazon DynamoDB. The Lambda function needs to read and write items to a DynamoDB table. What is the BEST way to securely provide the Lambda function with the necessary AWS credentials?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Create an IAM role with DynamoDB permissions and attach it to the Lambda function.. The best practice for granting AWS Lambda functions access to DynamoDB is to create an IAM role with the necessary DynamoDB permissions (e.g., dynamodb:GetItem, dynamodb:PutItem) and attach that role to the Lambda function. This follows the principle of least privilege and leverages AWS Identity and Access Management (IAM) roles, which provide temporary, automatically rotated credentials via the AWS Security Token Service (STS). This approach eliminates the need to manage long-term access keys and ensures secure, auditable access.

Answer

Store the AWS access key and secret key in the Lambda environment variables.

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Create an IAM user with programmatic access and store the credentials in the Lambda code.

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Use the Lambda function's default full admin access provided by AWS.

Question 2

A developer is troubleshooting an AWS Lambda function that is triggered by an S3 event. The function occasionally fails with a timeout error. CloudWatch logs show that the timeout occurs during the processing of large files. The function has a memory setting of 128 MB and a timeout of 3 seconds. The developer wants to process large files without modifying the code. Which parameter should the developer adjust first?

Accepted Answer

Increase the function's memory. Increasing the function's memory is the correct first step because Lambda allocates CPU proportionally to memory, and more CPU reduces processing time for CPU-bound tasks like decompressing or parsing large files. This directly addresses the timeout by making the function complete faster, without requiring code changes. The current 128 MB setting is the minimum, which provides the least CPU, so even a modest increase can significantly reduce execution time.

Answer

Increase the function's timeout

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Increase the function's reserved concurrency

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Increase the S3 event notification batch size

Question 3

A company wants to enforce multi-factor authentication (MFA) for all users accessing the AWS Management Console. The company has an existing IAM setup with users and groups. Which approach should the developer recommend to enforce MFA?

Accepted Answer

Attach an IAM policy to each user that denies all actions unless the user has MFA present.. It uses an IAM policy with a condition key (`aws:MultiFactorAuthPresent`) to deny all actions when MFA is not present. This is the standard AWS-recommended approach to enforce MFA for IAM users accessing the Management Console, as it applies a deny-all-except-MFA effect at the user level without requiring account-level changes.

Answer

Enable MFA at the account level using the AWS Account settings.

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Enable MFA on the root user and require all users to use the root user credentials with MFA.

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Create a new IAM group for MFA users and add users to that group.

Question 4

A developer is writing a Lambda function that processes events from an Amazon S3 bucket. The function needs to access a DynamoDB table to store metadata about the S3 objects. Which of the following is the MOST efficient way to initialize the DynamoDB client in the Lambda function?

Accepted Answer

Create the DynamoDB client outside the Lambda handler function, in the global scope.. Initializing the DynamoDB client outside the Lambda handler (in global scope) allows the client to be reused across multiple invocations within the same execution environment. This avoids the overhead of creating a new client on every invocation, which reduces latency and conserves resources. AWS Lambda reuses the global scope for subsequent invocations after the first, making this the most efficient approach.

Answer

Store the DynamoDB table name as a global variable and create the client inside the handler.

Answer

Use a static variable inside the handler to cache the DynamoDB client.

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Create the DynamoDB client inside the Lambda handler function every invocation.

Question 5

A developer is using the AWS CLI to deploy a new version of a Lambda function. The developer runs the following command:

aws lambda update-function-code --function-name my-function --zip-file fileb://my-code.zip

After the command completes, the developer checks the function and sees that the code has been updated but the version number is still $LATEST. The developer wants to create a new version so that the previous version is preserved. What should the developer do next?

Accepted Answer

Run the publish-version command to create a new version from the updated $LATEST.. The `update-function-code` command without the `--publish` flag only updates the `$LATEST` version of the Lambda function. To create an immutable, numbered version that preserves the previous code, the developer must explicitly run the `publish-version` command, which takes the current `$LATEST` code and publishes it as a new version (e.g., version 2). This ensures the previous version (version 1) remains unchanged and can be referenced via its version ARN.

Answer

Run the update-function-code command again with the --publish flag.

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Run the delete-function command and then create-function with the updated code.

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Run the update-function-configuration command to set the version number.

Question 6

A company hosts a web application on EC2 instances behind an ALB. The application uses cookies to track user sessions. The security team is concerned about session hijacking. Which action should be taken to protect the cookies?

Accepted Answer

Set the Secure and HttpOnly flags on the session cookie.. Setting the Secure and HttpOnly flags on the session cookie is the correct action because the Secure flag ensures the cookie is only sent over HTTPS, preventing interception via man-in-the-middle attacks, while the HttpOnly flag prevents client-side scripts (e.g., JavaScript) from accessing the cookie, mitigating cross-site scripting (XSS)-based session hijacking. This directly addresses the security team's concern by hardening the cookie against common attack vectors without requiring architectural changes.

Answer

Enable encryption on the ALB using a custom SSL certificate.

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Store session data in ElastiCache instead of cookies.

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Use AWS WAF to block requests without a valid session cookie.

Question 7

A developer is using AWS Lambda to process messages from an Amazon SQS queue. The function needs to access an Amazon DynamoDB table. What is the MOST secure way to grant the Lambda function access to DynamoDB?

Accepted Answer

Assign an IAM role to the Lambda function with a policy that grants the required DynamoDB permissions.. AWS Lambda uses an IAM execution role to securely obtain temporary credentials via the AWS Security Token Service (STS). By attaching a policy that grants only the required DynamoDB actions (e.g., GetItem, PutItem) on specific tables, you follow the principle of least privilege. This avoids hardcoding long-term credentials and eliminates the risk of credential exposure.

Answer

Use the Lambda function's execution role to grant full administrative access to DynamoDB.

Answer

Store the AWS access key and secret access key as environment variables in the Lambda function.

Answer

Create an IAM user with DynamoDB access and use its credentials in the Lambda function.

Question 8

A developer is using AWS CodeDeploy to deploy an application to an Auto Scaling group. The deployment must be as fast as possible while ensuring that at least 50% of instances remain healthy throughout. Which deployment configuration should be used?

Accepted Answer

CodeDeployDefault.HalfAtATime. CodeDeployDefault.HalfAtATime is the correct choice because it deploys to half of the instances in the Auto Scaling group at a time, ensuring that at least 50% of instances remain healthy throughout the deployment. This configuration balances speed (by deploying to multiple instances concurrently) with the required availability constraint, making it the fastest option that satisfies the 'at least 50% healthy' requirement.

Answer

CodeDeployDefault.OneAtATime

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CodeDeployDefault.AllAtOnce

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CodeDeployDefault.MinHealthyPercent

Question 9

A developer is building a microservices application composed of multiple AWS Lambda functions and an Amazon API Gateway. The developer needs to trace requests as they travel through different services to identify performance bottlenecks. Which AWS service should the developer integrate?

Accepted Answer

AWS X-Ray. AWS X-Ray is the correct service because it provides end-to-end tracing of requests as they travel through distributed applications, including AWS Lambda functions and API Gateway. It generates a service map that shows the flow of requests, latency breakdowns, and identifies performance bottlenecks across microservices. X-Ray integrates directly with Lambda and API Gateway via the X-Ray SDK and tracing headers, enabling trace propagation without code changes.

Answer

AWS CloudTrail

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Amazon CloudWatch Logs

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Amazon Inspector

Question 10

A developer needs to grant temporary access to an Amazon S3 bucket for a user from a different AWS account. The developer wants to use the most secure method that does not require sharing long-term credentials. Which approach should the developer take?

Accepted Answer

Use cross-account IAM roles with STS AssumeRole. Using cross-account IAM roles with AWS Security Token Service (STS) AssumeRole allows the external user to obtain temporary, limited-privilege credentials without sharing any long-term access keys. This approach follows the principle of least privilege and eliminates the risk of exposed static credentials, as the temporary credentials automatically expire after a configurable duration (default 1 hour, max 12 hours).

Answer

Create an IAM user in the developer's account and share the access keys

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Use S3 bucket policy with a condition for the external account's IAM user

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Use S3 access control lists (ACLs) with the external user's canonical user ID