SAA-C03 Exam Dumps - AWS Certified Solutions Architect - Associate (SAA-C03)

When an application is fronted by an Application Load Balancer (ALB) and malicious traffic is detected from a specific IP, the correct way to block the IP is by using AWS WAF (Web Application Firewall).

With AWS WAF, you can create an IP Set to include the offending IP address or range.

Then create a Web ACL (Access Control List) with a rule set to BLOCK requests from that IP set.

Finally, associate the Web ACL with the ALB.

Security groups (Option A) cannot deny specific IPs because they are stateful and allow-only rules.

Amazon Detective (Option B) is a security analysis and investigation tool; it doesn’t block traffic.

AWS RAM (Option C) is for resource sharing across accounts, not for blocking IPs.

This approach aligns with AWS’s Security Pillar of the Well-Architected Framework and is fully managed, with minimal operational effort.

🔗 Reference:

Using AWS WAF with an Application Load Balancer

Block IPs with AWS WAF

AWS Lambda for Operational Efficiency:

AWS Lambdais a serverless compute service that allows you to run code without provisioning or managing servers. It automatically scales based on the number of invocations and eliminates the need to maintain and monitor EC2 instances, making it far more operationally efficient compared to running a cron job on EC2.

By using Lambda, you pay only for the compute time that your function uses. This is especially beneficial when dealing with lightweight tasks, such as scanning a DynamoDB table and sending email messages once a day.

Amazon DynamoDB:

DynamoDBis a highly scalable, fully managed NoSQL database. The table stores employee start dates, and scanning the table to find the employees who have a work anniversary on the current day is a lightweight operation. Lambda can easily perform this operation using theDynamoDB Scan APIor queries, depending on how the data is structured.

Amazon SNS for Email Notifications:

Amazon Simple Notification Service (SNS)is a fully managed messaging service that supports sending notifications to a variety of endpoints, including email. SNS is well-suited for sendingout email messages to employees, as it can handle the fan-out messaging pattern (sending the same message to multiple recipients).

In this scenario, once Lambda identifies employees who have their work anniversaries, it can use SNS to send the email notifications efficiently. SNS integrates seamlessly with Lambda, and sending emails via SNS is a common pattern for this type of use case.

Event Scheduling:

To automate this daily task, you can schedule the Lambda function usingAmazon EventBridge (formerly CloudWatch Events). EventBridge can trigger the Lambda function on a daily schedule (cron-like scheduling). This avoids the complexity and operational overhead of manually setting up cron jobs on EC2 instances.

Why Not EC2 or SQS?:

Option A & Bsuggest running a cron job on anAmazon EC2instance. This approach requires you to manage, scale, and patch the EC2 instance, which increases operational overhead. Lambda is a better choice because it automatically scales and doesn’t require server management.

Amazon Simple Queue Service (SQS)is ideal for decoupling distributed systems but isn’t necessary in this context because the goal is to send notifications to employees on their work anniversaries. SQS adds unnecessary complexity for this straightforward use case, whereSNSis the simpler and more efficient solution.

AWS References:

AWS Lambda

Amazon SNS

Amazon DynamoDB

Amazon EventBridge

Summary:

UsingAWS Lambdacombined withAmazon SNSto send notifications, and scheduling the function withAmazon EventBridgeto run daily, is the most operationally efficient solution. It leverages AWS serverless technologies, which reduce the need for infrastructure management and provide automatic scaling. Therefore,Option Cis the correct and optimal choice.

Comprehensive and Detailed Step-by-Step Explanation:

The requirement is toprevent Application A from sending traffic to Application B.

Understanding AWS Network Security Components:

Security Groups

Stateful(if traffic is allowed in one direction, it is automatically allowed in the reverse).

Do not support explicit deny rules, onlyallow rules.

Not suitable for blocking traffic in this scenario.

Network ACLs (NACLs)

Stateless(must define explicit rules for both inbound and outbound traffic).

Support explicit DENY rules.

Best suited for blocking traffic between subnets.

Analysis of the Options:

Option A: Deny Outbound Rule in Security Group for Application B❌(Incorrect)

Security Groups do not support explicit deny rules.

Does not block traffic from Application A to Application B.

Option B: Deny Outbound Rule in Security Group for Application A❌(Incorrect)

Security Groups do not support explicit deny rules.

Cannot effectively prevent Application A from sending traffic to Application B.

Option C: Deny Outbound Rule in NACL for Application B Subnet❌(Incorrect)

This wouldprevent Application B from sending traffic, butthe requirement is to block traffic from Application A to Application B.

Incorrect subnet is being modified.

Option D: Deny Outbound Rule in NACL for Application A Subnet✅(Correct Choice)

Prevents Application A from sending traffic to Application B by blocking outbound requests at the network level.

Effectively stops communication from A to B at the subnet level.

Why Option D is the Best Choice?

✅NACLs support explicit deny rules, unlike security groups.✅Blocks outbound traffic from Application A before it reaches Application B.✅Works at the subnet level, making it scalable.

SSE-KMS: Server-side encryption with AWS Key Management Service (SSE-KMS) provides robust encryption of data at rest, integrated with AWS KMS for key management and auditing.

Automatic Key Rotation: By enabling automatic rotation for the KMS keys, the system ensures that keys are rotated annually without manual intervention, meeting compliance requirements.

Logging and Auditing: AWS KMS automatically logs all key usage and management actions in AWS CloudTrail, providing the necessary audit logs.

Implementation:

Create a KMS key with automatic rotation enabled.

Configure the S3 bucket to use SSE-KMS with the created KMS key.

Ensure CloudTrail is enabled for logging KMS key usage.

Operational Efficiency: This solution provides encryption, automatic key management, and auditing in a seamless, fully managed way, reducing operational overhead.

Amazon ECS with AWS Fargate provides serverless container compute that can scale tasks dynamically in response to demand. This matches the unpredictable scaling requirements of a gaming workload. Aurora Serverless v2 provides on-demand, autoscaling relational database capacity while supporting complex SQL queries. EC2 with Auto Scaling (A) works but requires significant management overhead. Lambda with DynamoDB (B) is not suitable because the workload requires a relational database and long-running processes. ParallelCluster with HPC (D) is designed for batch scientific workloads, not dynamic, interactive gaming. Option C provides the correct balance of elasticity, performance, and managed services for both compute and relational database needs.

The question focuses on minimizing costs while serving static content to users in the US and Europe.

Option Auses a single S3 bucket and configures CloudFront to limit edge locations, reducing costs by using fewer edge locations while still improving performance.

Option Bmaximizes edge locations, which increases costs unnecessarily.

Options C and Dinvolve storing data in multiple regions, which increases storage and operational costs.Thus, Option A is the most cost-effective solution.

Correct Approach:

AWS Security Groups:

Security groups operate at the instance level, making them the ideal tool for controlling access to specific resources such as an Amazon RDS database.

By default, security groups deny all incoming traffic. You can allow access by explicitly specifying another security group.

Associating an RDS database security group with the EC2 instances' security group ensures only the specified EC2 instances can access the RDS database.

Incorrect Options Analysis:

Option A: Using CIDR blocks for IP-based access is less secure and more difficult to manage. Additionally, Auto Scaling groups dynamically allocate IP addresses, making this approach impractical.

Option B: Network ACLs (NACLs) operate at the subnet level and are stateless. While NACLs can deny or allow traffic, they are not suited to application-specific access control.

Option D: Similar to Option B, using a NACL with CIDR ranges for EC2 IPs is difficult to manage and not application-specific.