ISC2 CC Practice Question: Business Continuity, Disaster Recovery, and Incident Response
A company experiences a ransomware attack that encrypts all files on a file server. The IT team decides to restore the server from the most recent full backup taken 24 hours ago, followed by all differential backups taken since then. If the last full backup was on Sunday at midnight, and the attack occurs on Wednesday at 6:00 AM, with differential backups taken daily at noon, how many differential backups must be restored?
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
✓
2
Differential backups contain changes since the last full backup. The last full backup was Sunday midnight. Differential backups were taken Monday noon, Tuesday noon, and Wednesday noon (but the attack was at 6 AM Wednesday, so Wednesday's backup hadn't occurred yet). So differential backups available: Monday and Tuesday. That's 2 differential backups to restore.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
3
Why it's wrong here
Three would include Wednesday's backup which wasn't taken yet.
- ✗
4
Why it's wrong here
Too many; only two are available.
- ✗
1
Why it's wrong here
Only one differential backup is not enough; two were taken since the full backup.
- ✓
2
Why this is correct
Two differential backups (Monday and Tuesday) were taken after the full backup and before the attack.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CC 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 CC exam.