Quick Answer
The answer is firewall and antivirus software. These are classic examples of preventive security controls because they actively block or stop attacks before they can cause harm—a firewall filters incoming and outgoing network traffic based on security rules, while antivirus software detects and quarantines malicious code before it executes. On the ISC2 Certified in Cybersecurity CC exam, this concept tests your ability to distinguish preventive controls from detective, corrective, or deterrent measures; a common trap is confusing an intrusion detection system (IDS), which only alerts after an incident, with a preventive tool. Remember that preventive controls are like a locked door—they stop entry—whereas detective controls are like a security camera that watches after the fact. A simple memory tip is to think of the word “block”: firewalls and antivirus both block threats, so they are preventive.
This CC practice question tests your understanding of security principles. 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.
Which TWO of the following are examples of preventive security controls?
Encryption
Why wrong: Encryption protects data but is not typically classified as preventive.
Backup
Why wrong: Backup is a corrective control for recovery.
Antivirus software
Antivirus prevents malware execution.
Firewall
Firewalls block unauthorized traffic, preventing attacks.
Intrusion detection system
Why wrong: IDS detects but does not prevent intrusions.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Antivirus software
Firewalls and antivirus software are preventive controls that block or stop attacks. IDS is detective, encryption is protective but not primarily preventive, and backup is corrective.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Encryption
Why it's wrong here
Encryption protects data but is not typically classified as preventive.
Backup
Why it's wrong here
Backup is a corrective control for recovery.
Antivirus software
Why this is correct
Antivirus prevents malware execution.
Related concept
Read the scenario before looking for a memorised answer.
Firewall
Why this is correct
Firewalls block unauthorized traffic, preventing attacks.
Related concept
Read the scenario before looking for a memorised answer.
Intrusion detection system
Why it's wrong here
IDS detects but does not prevent intrusions.
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A developer is choosing between AES-256 (symmetric) and RSA-2048 (asymmetric) for encrypting a large file that will be sent to a partner. Symmetric encryption is fast but requires key exchange; asymmetric is slower but solves the key distribution problem. A hybrid approach — encrypt the file with AES, encrypt the AES key with RSA — is standard. Questions like this test whether you understand when each approach applies.
What to study next
Identify which CC exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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FAQ
Security Principles — This question tests Security Principles — Read the scenario before looking for a memorised answer..
The correct answer is: Antivirus software — Firewalls and antivirus software are preventive controls that block or stop attacks. IDS is detective, encryption is protective but not primarily preventive, and backup is corrective.
Identify which CC exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
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.
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