This CCSP practice question tests your understanding of cloud application security. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company is adopting a serverless architecture using AWS Lambda. The security team is concerned about potential injection attacks via event payloads. Which practice is most effective at mitigating such attacks?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Validate and sanitize all input data from event sources
Option C is correct because serverless functions like AWS Lambda are directly invoked by event payloads, and without input validation and sanitization, an attacker can inject malicious code (e.g., SQL, NoSQL, OS commands) that the function executes. This is the most effective mitigation as it addresses the root cause at the application layer, regardless of any perimeter controls.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Use a web application firewall (WAF) in front of the API Gateway
Why it's wrong here
WAF only covers HTTP triggers, not other event sources like S3 or SQS.
✗
Assign the least privilege IAM role to each Lambda function
Why it's wrong here
Least privilege limits damage but does not prevent injection.
✓
Validate and sanitize all input data from event sources
Why this is correct
Input validation prevents malicious payloads from being processed.
Related concept
Read the scenario before looking for a memorised answer.
Encryption protects secrets but does not address injection.
Common exam traps
Common exam trap: answer the scenario, not the keyword
ISC2 often tests the misconception that perimeter controls (like WAFs) or IAM permissions are sufficient to prevent application-layer attacks, but the trap here is that injection vulnerabilities are code-level flaws that only input validation can directly remediate.
Detailed technical explanation
How to think about this question
Injection attacks in serverless functions exploit the fact that the runtime (e.g., Node.js, Python) directly processes event fields (e.g., `event['body']`, `event['Records']`) without escaping. For example, if a Lambda function concatenates user input into a SQL query string, an attacker can inject `' OR 1=1 --` to bypass authentication. Input validation should follow a whitelist approach (e.g., regex patterns, type checks) rather than blacklisting, and sanitization must escape special characters per the target context (e.g., parameterized queries for SQL, `exec` wrappers for shell commands).
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A SOC analyst notices unusual lateral movement in the network at 2 AM. The IR playbook dictates: identify and contain (isolate the affected machine), then eradicate (remove the malware), then recover (restore from backup), then document. Skipping containment before eradication risks the attacker regaining access. Questions like this test the sequence and rationale of incident response phases.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Cloud Application Security — This question tests Cloud Application Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Validate and sanitize all input data from event sources — Option C is correct because serverless functions like AWS Lambda are directly invoked by event payloads, and without input validation and sanitization, an attacker can inject malicious code (e.g., SQL, NoSQL, OS commands) that the function executes. This is the most effective mitigation as it addresses the root cause at the application layer, regardless of any perimeter controls.
What should I do if I get this CCSP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This CCSP practice question is part of Courseiva's free ISC2 certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CCSP exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.