Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A company runs a public-facing e-commerce website on Amazon EC2 instances behind an Application Load Balancer (ALB). The security team has discovered that attackers are attempting SQL injection attacks through the website's search feature. The company wants to use a managed AWS service to inspect incoming HTTP requests and block these malicious payloads before they reach the application. Which AWS service should the company use?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
AWS Shield Standard
AWS Shield Standard provides always-on protection against common DDoS attacks at the network and transport layer, but it does not inspect application-layer content like SQL injection payloads. It cannot block or filter specific HTTP requests.
B
Best answer
AWS WAF
AWS WAF is a web application firewall that inspects HTTP and HTTPS requests and can block common threats such as SQL injection and cross-site scripting. It integrates directly with Application Load Balancers, Amazon CloudFront, and API Gateway, making it the correct service for this use case.
C
Distractor review
Network ACLs
Network ACLs are stateless firewalls that control traffic at the subnet level based on IP addresses, ports, and protocols. They cannot inspect the contents of HTTP requests or block application-layer attacks like SQL injection.
D
Distractor review
Amazon GuardDuty
Amazon GuardDuty is a threat detection service that continuously monitors for malicious activity and unauthorized behavior using machine learning and threat intelligence. It can detect SQL injection attempts in logs, but it does not actively block the requests; it only generates alerts.
Common exam trap
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Technical deep dive
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
- CIDR notation defines the prefix length.
- Block size helps identify subnet boundaries.
- Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
- The required host count determines the smallest suitable subnet.
TExam Day Tips
- Write the block size before choosing the subnet.
- Check whether the question asks for hosts, subnets or a specific address range.
- Do not confuse /24, /25, /26 and /27 host counts.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A developer needs to launch a test server for a new application prototype. The developer logs into the AWS Management Console, selects an Amazon EC2 instance type, configures the security group, and starts the instance. The instance is running within two minutes, and the developer did not need to submit a formal request to the company's IT procurement team or wait for approval from a cloud administrator. Which essential characteristic of cloud computing does this scenario best demonstrate?
Question 2
A solutions architect is planning a new web application on AWS. The workload will include 3 Amazon EC2 instances (t3.medium) running 24/7, an Application Load Balancer, and an Amazon RDS for MySQL db.t3.small database. The architect needs to estimate the monthly cost for the first year, considering different purchasing options (On-Demand, 1-year All Upfront Reserved Instance, and Compute Savings Plan). Which AWS tool should the architect use to create this estimate?
Question 3
A company's development team frequently needs temporary test environments. A developer can log into the AWS Management Console, select an Amazon EC2 instance type, configure storage, and launch the instance within minutes without any interaction with the IT infrastructure team. This capability is an example of which essential characteristic of cloud computing?
Question 4
A company's finance team needs to analyze AWS spending in detail. They require a report that includes hourly cost data for each AWS service, each individual resource (e.g., a specific EC2 instance), and any cost allocation tags applied. The team plans to export this data to an Amazon S3 bucket and then import it into a custom business intelligence (BI) analytics dashboard. Which AWS tool should the finance team use to generate this level of detailed cost data?
Question 5
A company uses AWS for its development environment. The finance team wants to set a monthly budget of $10,000. They want to receive an email notification when the actual costs reach 80% of the budget ($8,000) and again when costs exceed the budget. The team needs a managed AWS service that can automatically send these alerts without requiring custom code or third-party tools. Which AWS service should the team use?
Question 6
A company uses AWS Organizations to manage multiple accounts. The security team needs to enforce a policy that restricts SSH access (port 22) from the internet (0.0.0.0/0) in all VPCs across all accounts. The team wants to centrally define the allowed rules and automatically apply them to newly created VPCs and security groups, while also automatically remediating any existing non-compliant security groups. Which AWS service should the team use?
FAQ
Questions learners often ask
What does this CLF-C02 question test?
CIDR notation defines the prefix length.
What is the correct answer to this question?
The correct answer is: AWS WAF — AWS WAF is a web application firewall that protects web applications from common web exploits, including SQL injection and cross-site scripting. It can be attached to an Application Load Balancer, API Gateway, or CloudFront to filter and block malicious requests based on customizable rules. AWS Shield Standard provides basic DDoS protection but does not inspect application-layer payloads. Network ACLs operate at the subnet level and cannot inspect HTTP content. Amazon GuardDuty is a threat detection service; it generates security findings but does not actively block incoming web requests.
What should I do if I get this CLF-C02 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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