DVA-C02 Practice Exam 4 — 20 Questions

Question 1

A company has an S3 bucket containing confidential data. The security team wants to ensure that the bucket is never publicly accessible, even if a bucket policy or ACL is incorrectly set to allow public access. Which S3 feature should the developer enable?

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

Accepted Answer

Enable S3 Block Public Access (bucket-level).. S3 Block Public Access (bucket-level) provides a definitive override that prevents any public access to the bucket, regardless of any bucket policies or ACLs that might otherwise grant public access. This feature acts as a safety net, ensuring that even if a policy or ACL is misconfigured to allow public access, the block public access settings will deny all public requests at the S3 service level before any policy evaluation occurs.

Answer

Enable S3 Transfer Acceleration to ensure faster uploads.

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Enable S3 Server Access Logging to monitor access.

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Enable S3 Object Lock to prevent objects from being deleted.

Question 2

A developer is deploying a containerized application on Amazon ECS with Fargate. The application requires access to an Amazon RDS database. The developer needs to securely pass database credentials to the container. Which THREE methods can the developer use?

Accepted Answer

Store the credentials in AWS Systems Manager Parameter Store and reference the parameter in the task definition.. Options A, B, and C are correct because they all provide secure, native mechanisms for delivering RDS credentials to an ECS Fargate task. Option A is right because ECS task definitions support the secrets parameter with valueFrom pointing to a Systems Manager Parameter Store parameter (for example, arn:aws:ssm:region:account:parameter/name), and the value is injected at container start without being baked into the image. Option B is right because ECS also supports referencing AWS Secrets Manager secrets in the task definition's secrets block, allowing the credential to be fetched and injected securely at runtime. Option C is right because an IAM task role can grant the container permission to call secretsmanager:GetSecretValue (or ssm:GetParameter) at runtime, letting the application retrieve credentials dynamically without embedding them. Option D is wrong because hardcoding credentials in the container image exposes them to anyone who can pull or inspect the image and violates credential-rotation best practices. Option E is wrong because defining credentials as plaintext environment variables in the task definition stores them in the task definition itself, making them visible to anyone with ECS read access and not securely encrypted or rotated.

Answer

Hardcode the credentials in the container image.

Answer

Define environment variables in the task definition with the credentials.

Question 3

A developer runs an application on Amazon EC2 that needs to securely store database credentials (username and password). The security team requires that the credentials be automatically rotated every 30 days. Which AWS service should the developer use to store and automatically rotate the credentials?

Accepted Answer

AWS Secrets Manager with automatic rotation enabled.. AWS Secrets Manager is designed specifically for managing secrets such as database credentials, with built-in capabilities for automatic rotation according to a schedule (e.g., every 30 days). It integrates natively with supported databases (e.g., Amazon RDS, Redshift, DocumentDB) to rotate credentials without custom code, and it encrypts secrets at rest using AWS KMS. This makes it the correct choice for the developer's requirement of secure storage and automated rotation.

Answer

AWS Systems Manager Parameter Store with a SecureString parameter.

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AWS Identity and Access Management (IAM) roles for EC2.

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AWS Key Management Service (KMS) to store the credentials as encrypted data.

Question 4

A developer is troubleshooting an AWS Lambda function that is invoked from an Amazon S3 bucket via event notifications. The function processes images and stores metadata in Amazon DynamoDB. The developer notices that some images are being processed multiple times, resulting in duplicate entries in DynamoDB. The S3 event notification is configured to send events to the Lambda function with the 's3:ObjectCreated:*' event type. The function uses the 'uuid' library to generate a unique ID for each image upon processing. What is the most likely cause of the duplicate processing?

Accepted Answer

S3 event notifications are delivered at least once, and the Lambda function is not idempotent.. Amazon S3 event notifications are delivered on an 'at least once' basis, meaning the same event can be sent to Lambda multiple times. If the Lambda function is not idempotent—i.e., processing the same event multiple times produces duplicate side effects—then duplicate DynamoDB entries will occur. The use of a 'uuid' library inside the function does not help because a new UUID is generated on each invocation, so the same image gets different IDs and is stored as a separate item each time.

Answer

The Lambda function's concurrency is set too high, causing race conditions.

Answer

The DynamoDB table does not have a primary key that prevents duplicates.

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The S3 bucket is configured with versioning, causing multiple object creation events.

Question 5

A company uses AWS Elastic Beanstalk to deploy a web application. The application requires a database connection string that is different for each environment (development, staging, production). The developer wants to set these values without hardcoding them in the application code. Which configuration method should the developer use?

Accepted Answer

Use environment properties in the Elastic Beanstalk console. Elastic Beanstalk environment properties allow you to inject configuration values (like database connection strings) into your application at deployment time without hardcoding them. These properties are set per environment in the Elastic Beanstalk console or via CLI, and the application retrieves them as environment variables, making them environment-specific. While database connection strings are sensitive, environment properties are the simplest configuration method within Elastic Beanstalk for such values. AWS Systems Manager Parameter Store (Option D) is more secure for secrets but is not a native Elastic Beanstalk feature and requires additional setup; the question specifically asks for a configuration method within Elastic Beanstalk's native capabilities.

Answer

Use the .ebextensions configuration files with environment-specific snippet files

Answer

Use Amazon RDS within Elastic Beanstalk

Answer

Use AWS Systems Manager Parameter Store with an IAM instance profile

Question 6

A company has multiple AWS accounts managed under AWS Organizations. The security team requires that all Amazon S3 buckets with bucket names containing 'logs' must be encrypted with a specific KMS key (key ID: alias/logs-key) at rest. A developer must enforce this using an SCP (Service Control Policy). Which SCP effect and condition key should be used to deny any PutObject request that does not use the required KMS key?

Accepted Answer

Deny effect with a Condition: StringNotEquals on s3:x-amz-server-side-encryption-aws-kms-key-id. SCPs use a Deny effect to block non-compliant requests. The condition key `s3:x-amz-server-side-encryption-aws-kms-key-id` with `StringNotEquals` ensures that any PutObject request that does not specify the exact KMS key alias/logs-key is denied. This enforces encryption with the required key for all S3 buckets containing 'logs' in their name.

Answer

Deny effect with a Condition: StringEquals on s3:x-amz-server-side-encryption

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Allow effect with a Condition: StringEquals on kms:RequestTag/key-id

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Deny effect with a Condition: IpAddress on aws:SourceIp

Question 7

A company wants to build a RESTful API that handles file uploads. The API needs to support multipart/form-data content type. The developer is using Amazon API Gateway and AWS Lambda. Which approach should the developer use to handle file uploads efficiently?

Accepted Answer

Use API Gateway to generate a presigned S3 URL, and have the client upload directly to S3. The Lambda function can then process the file asynchronously.. It offloads the file upload to Amazon S3 directly via a presigned URL, which avoids the 10 MB payload limit and 29-second timeout of API Gateway and Lambda for large files. The client uploads the file to S3, and a separate Lambda function processes the file asynchronously, making the solution efficient and scalable for multipart/form-data uploads.

Answer

Configure API Gateway to pass the entire request body to Lambda, and process the file within the Lambda function.

Answer

Create a Lambda function that accepts the file and uploads it to S3 using the AWS SDK.

Answer

Use an EC2 instance to host a custom web server that accepts file uploads and writes to S3.

Question 8

A developer stores database credentials for an application running on Amazon EC2. The security team requires that the credentials be automatically rotated every 30 days to reduce the risk of compromise. Which AWS service should the developer use to store and automatically rotate the credentials?

Accepted Answer

AWS Secrets Manager. AWS Secrets Manager is the correct choice because it is specifically designed to securely store database credentials and other secrets, and it provides built-in, configurable automatic rotation (e.g., every 30 days) using AWS Lambda. This meets the security team's requirement without custom scripting or infrastructure management.

Answer

AWS Systems Manager Parameter Store

Answer

AWS Key Management Service (KMS)

Answer

IAM Roles for EC2

Question 9

A developer is using AWS CodeDeploy to deploy an application to an EC2 Auto Scaling group. The developer wants to monitor the deployment and automatically roll back if a specified Amazon CloudWatch alarm is triggered during the deployment. Which CodeDeploy feature should the developer configure?

Accepted Answer

Deployment group alarm configuration. The Deployment group alarm configuration in AWS CodeDeploy allows you to specify Amazon CloudWatch alarms that, when triggered during a deployment, automatically initiate a rollback. This feature is configured at the deployment group level and ensures that if a predefined alarm (e.g., high error rate or latency) enters the ALARM state, CodeDeploy stops the deployment and reverts to the last known good revision. This provides automated, policy-driven rollback without manual intervention.

Answer

Deployment configuration with alarm

Answer

Revision rollback

Answer

EC2 instance health check

Question 10

A developer is building a REST API using Amazon API Gateway and AWS Lambda. The API needs to support a custom domain name and an SSL/TLS certificate. Which AWS service should the developer use to manage the SSL/TLS certificate?

Accepted Answer

AWS Certificate Manager (ACM). AWS Certificate Manager (ACM) is the correct service for provisioning, managing, and deploying SSL/TLS certificates for use with AWS services like API Gateway. ACM integrates directly with API Gateway to automatically renew certificates and attach them to custom domain names, ensuring secure HTTPS connections without manual intervention.

Answer

AWS Key Management Service (AWS KMS)

Answer

AWS Identity and Access Management (IAM)

Answer

AWS Secrets Manager

Question 11

A developer is building a serverless application that uses Amazon S3 event notifications to trigger an AWS Lambda function for thumbnail generation. The developer wants to ensure that duplicate S3 events do not cause the same image to be processed multiple times. Which approach should the developer implement to ensure idempotent processing?

Accepted Answer

Store the object key and event ID in a DynamoDB table and check for duplicates before processing. Storing the S3 object key and event ID in a DynamoDB table with a TTL attribute allows the Lambda function to perform a conditional write (or check for an existing item) before processing. This ensures that even if duplicate S3 events are delivered (e.g., due to S3's at-least-once delivery guarantee), the same image is only processed once, achieving idempotency.

Answer

Set the Lambda function's concurrency to 1 to prevent concurrent executions

Answer

Use an Amazon SQS FIFO queue as the event destination

Answer

Enable S3 event notification filtering based on object size

Question 12

A developer is building a REST API using Amazon API Gateway and wants to transform the request data before sending it to the backend Lambda function. The transformation includes mapping query string parameters to a JSON body. Which API Gateway feature should be used?

Accepted Answer

Velocity Template Language (VTL) mapping templates. API Gateway uses Velocity Template Language (VTL) mapping templates to transform incoming request data, such as mapping query string parameters into a JSON body before passing it to the backend Lambda function. This feature allows you to define a template that extracts values from the request's query string parameters (e.g., `$input.params('paramName')`) and constructs a new JSON payload, enabling seamless integration with Lambda without modifying the client request.

Answer

Lambda authorizer

Answer

Request validator

Answer

CORS configuration

Question 13

A developer is building a serverless application using an API Gateway HTTP API and Lambda. The developer needs to authenticate users with a JWT token. Which API Gateway feature should be used?

Accepted Answer

JWT Authorizer. API Gateway HTTP APIs support JWT Authorizers natively. This feature allows API Gateway to validate JSON Web Tokens (JWTs) directly without invoking a Lambda function, verifying the token's signature, expiry, and issuer against a configured identity provider (such as Amazon Cognito or any OIDC-compliant provider). This is the most efficient and cost-effective way to handle JWT authentication in HTTP APIs.

Answer

Lambda Authorizer

Answer

IAM Authorizer

Answer

Amazon Cognito User Pools

Question 14

A developer is creating a new DynamoDB table to store order data. The orders have a unique order ID and are retrieved by order ID. Occasionally, the developer needs to query orders by customer ID. Which design approach would minimize costs and provide the fastest queries?

Accepted Answer

Use the order ID as the partition key and create a global secondary index on customer ID. Using the order ID as the partition key ensures the most efficient primary key access for the primary query pattern (retrieving by order ID). Creating a Global Secondary Index (GSI) on customer ID allows efficient querying by customer ID without scanning the base table, and GSIs have separate read/write capacity from the base table, so you only pay for the index when it is used. This design minimizes costs by avoiding unnecessary scans and provides the fastest queries for both access patterns.

Answer

Use the customer ID as the partition key and order ID as the sort key

Answer

Use the order ID as the partition key and scan the table for customer ID queries

Answer

Use the customer ID as the partition key and create a local secondary index on order ID

Question 15

A developer needs to store application configuration data (key-value pairs) that can be accessed by multiple microservices running on EC2 instances. The configuration data changes infrequently but must be retrievable with low latency. Which AWS service should the developer use?

Accepted Answer

AWS Systems Manager Parameter Store. AWS Systems Manager Parameter Store is designed specifically to store configuration data (such as database strings, license codes, or general key-value pairs) and secrets. It provides a centralized, secure, and hierarchical store that can be easily accessed by EC2 instances and microservices with low latency. Standard parameters are free of charge, making it the ideal choice for infrequently changing configuration data.

Answer

AWS AppConfig

Answer

Amazon S3

Answer

Amazon DynamoDB

Question 16

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?

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.

Answer

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

Answer

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

Question 17

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

Answer

Increase the function's reserved concurrency

Answer

Increase the S3 event notification batch size

Question 18

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.

Answer

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

Answer

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

Question 19

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.

Answer

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

Question 20

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.

Answer

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

Answer

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