DEA-C01 Data Security and Governance Practice Question
A financial services company uses AWS Glue ETL jobs to process credit card transaction data stored in Amazon S3. The data includes PII such as names and credit card numbers. The security team requires that all PII be masked before the data is written to the curated zone of the data lake. The data engineer has implemented a Glue job that reads from the raw zone, applies a custom transform to mask credit card numbers using a regular expression, and writes to the curated zone. However, during a recent audit, the security team discovered that some masked data still contained partial credit card numbers (e.g., showing the last four digits) when viewed by analysts who should only see masked data. The company's policy is that credit card numbers must be completely masked, showing only asterisks or a fixed string like "XXXX-XXXX-XXXX-XXXX". The Glue job uses a DynamicFrame and applies a Map transform with a Python function that replaces digits with 'X'. The data is stored in Parquet format. What should the data engineer do to ensure complete masking of credit card numbers?
⚠ Common exam trap
A common mix-up: candidates assume any custom Python logic with a regex is sufficient for masking, but the exam tests the understanding that AWS Glue's built-in Mask transform provides a more reliable and policy-compliant solution for sensitive data obfuscation.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Replace the custom Python Map transform with a built-in Glue Transform for data masking, such as the Mask transform available in Glue Studio.
AWS Glue provides a built-in Mask transform that can be applied directly in Glue Studio or via the AWS Glue API. This transform is designed to reliably obfuscate sensitive data like credit card numbers by replacing them with a fixed string (e.g., 'XXXX-XXXX-XXXX-XXXX') or asterisks, ensuring complete masking regardless of input format. The custom Python Map transform in the current implementation is error-prone because it relies on a regular expression that may not catch all patterns or partial digits, whereas the Mask transform uses predefined logic to guarantee full masking.
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 an AWS Glue crawler to classify the data and apply a masking rule based on the classification.
Why it's wrong here
Crawlers classify schemas but do not mask data; masking must be part of the ETL job.
- ✗
Enable server-side encryption with AWS KMS on the curated S3 bucket.
Why it's wrong here
Encryption protects data at rest but does not mask the content for authorized users.
- ✓
Replace the custom Python Map transform with a built-in Glue Transform for data masking, such as the Mask transform available in Glue Studio.
Why this is correct
Built-in masking transforms are designed to handle common patterns and ensure complete masking.
- ✗
Change the output format from Parquet to CSV and use a different write mode.
Why it's wrong here
Format change does not fix masking logic.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DEA-C01 practice question is part of Courseiva's free Amazon Web Services 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 DEA-C01 exam.