This CCSP practice question tests your understanding of cloud data security. Compare every option against the stated constraints before choosing — the best answer satisfies all requirements, not just the most obvious one. 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.
An organization uses a cloud-based DLP solution to monitor outbound traffic. They want to prevent the exfiltration of credit card numbers. Which detection technique is most appropriate for this requirement?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Regular expression matching for credit card number patterns
Regular expression matching (option D) is the most appropriate technique because credit card numbers follow well-defined, predictable patterns (e.g., 16 digits, specific starting digits for each issuer like 4 for Visa, 5 for MasterCard, and Luhn algorithm validation). This allows the DLP solution to detect credit card numbers in outbound traffic without requiring a pre-populated list or prior training, making it ideal for real-time monitoring of unknown or new card numbers.
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.
✗
Exact data matching against a list of known card numbers
Why it's wrong here
Exact matching requires a prior list, which may not be available.
✗
Machine learning classification of sensitive data
Why it's wrong here
ML is less deterministic and may have false positives/negatives.
✗
Fingerprinting of known credit card documents
Why it's wrong here
Fingerprinting detects known files, not arbitrary data patterns.
✓
Regular expression matching for credit card number patterns
Why this is correct
Regex can identify card numbers based on format.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
ISC2 often tests the misconception that machine learning (option B) is always the most advanced or accurate technique, but for structured data like credit card numbers, regex is simpler, faster, and more precise.
Detailed technical explanation
How to think about this question
Under the hood, regular expression matching for credit card numbers typically uses patterns like `\b(?:4[0-9]{12}(?:[0-9]{3})?|5[1-5][0-9]{14}|3[47][0-9]{13})\b` combined with Luhn algorithm checks to reduce false positives. In a real-world scenario, a DLP solution like Symantec or McAfee can apply this regex to SMTP, HTTP, or FTP traffic to block exfiltration in real time, even if the card number is split across multiple packets or obfuscated with spaces.
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 security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
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 Data Security — This question tests Cloud Data Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Regular expression matching for credit card number patterns — Regular expression matching (option D) is the most appropriate technique because credit card numbers follow well-defined, predictable patterns (e.g., 16 digits, specific starting digits for each issuer like 4 for Visa, 5 for MasterCard, and Luhn algorithm validation). This allows the DLP solution to detect credit card numbers in outbound traffic without requiring a pre-populated list or prior training, making it ideal for real-time monitoring of unknown or new card numbers.
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.
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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
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