The answer is that the key was stored in a publicly accessible Cloud Storage bucket. This violates the core security best practice of never exposing service account private keys to unauthorized users, as any entity with read access to that bucket can retrieve the JSON key and impersonate the service account, gaining full access to Google Cloud resources. On the Google Professional Cloud Developer exam, this scenario tests your understanding of credential management and the principle of least privilege—a common trap is focusing on the key’s format or rotation rather than its public exposure. Remember that service account keys should always be stored in a secrets manager like Secret Manager, never in a bucket, even if the bucket is intended to be private. A simple memory tip: “Keys in buckets are public hacks waiting to happen.”
PCD Practice Question: Designing highly scalable, available, and reliable cloud-native applications
This PCD practice question tests your understanding of designing highly scalable, available, and reliable cloud-native applications. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
Network Topology
A developer finds the JSON key shown in the exhibit in a Cloud Storage bucket that is publicly accessible. Which security best practice was violated?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The key was stored in a publicly accessible Cloud Storage bucket.
Option D is correct because storing a JSON key (a service account private key) in a publicly accessible Cloud Storage bucket directly violates the principle of least privilege and exposes sensitive credentials to unauthorized users. Any entity with read access to the bucket can retrieve the key and impersonate the service account, potentially gaining unauthorized access to Google Cloud resources.
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.
✗
The key is not rotated regularly.
Why it's wrong here
Rotation is important but not the immediate violation.
✗
The key was created as a user-managed key instead of a Google-managed key.
Why it's wrong here
User-managed keys are allowed; the issue is storage.
✗
The key was not encrypted using Cloud KMS.
Why it's wrong here
While encryption is good, the primary violation is public access.
✓
The key was stored in a publicly accessible Cloud Storage bucket.
Why this is correct
Service account keys must be kept confidential and never exposed publicly.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between encryption (which protects data at rest) and access control (which governs who can read the data), leading candidates to mistakenly choose an encryption-related option when the real issue is public exposure.
Detailed technical explanation
How to think about this question
Service account keys are JSON or P12 files containing a private key that can be used to authenticate API calls via OAuth 2.0. When stored in a publicly accessible bucket, any user with the bucket URL can download the key and generate access tokens, effectively bypassing IAM policies. This is a common misconfiguration in Cloud Storage where bucket ACLs or uniform bucket-level access are not properly enforced, leading to data exposure.
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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
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.
Designing highly scalable, available, and reliable cloud-native applications — This question tests Designing highly scalable, available, and reliable cloud-native applications — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The key was stored in a publicly accessible Cloud Storage bucket. — Option D is correct because storing a JSON key (a service account private key) in a publicly accessible Cloud Storage bucket directly violates the principle of least privilege and exposes sensitive credentials to unauthorized users. Any entity with read access to the bucket can retrieve the key and impersonate the service account, potentially gaining unauthorized access to Google Cloud resources.
What should I do if I get this PCD question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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This PCD practice question is part of Courseiva's free Google Cloud 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 PCD exam.
Question Discussion
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