Question 481 of 1,000

Software Development Security →easyMultiple ChoiceObjective-mapped

CISSP Software Development Security Practice Question

Q: How is Software Development Security tested on the CISSP exam?

Software Development Security — This question tests Software Development Security — Read the scenario before looking for a memorised answer..

Q: What is the correct answer to this Software Development Security CISSP question?

The correct answer is: Preventing cross-site scripting (XSS) attacks — Output encoding is the practice of converting special characters (e.g., , &, ") into their corresponding HTML entities (e.g., < > & ") before sending data to the browser. This ensures that any user-supplied data is treated as text, not executable code, thereby neutralizing injected scripts. It is the primary defense against stored, reflected, and DOM-based cross-site scripting (XSS) attacks because it breaks the parser's ability to interpret the data as active content.

This CISSP practice question tests your understanding of software development security. 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 of the following is the primary purpose of output encoding in web application security?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

Clue: "primary"
Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.

A
Preventing buffer overflow attacks
Why wrong: Buffer overflows are prevented by proper memory management and bounds checking.
B
Preventing cross-site request forgery (CSRF)
Why wrong: CSRF is prevented by CSRF tokens, not output encoding.
C
Preventing cross-site scripting (XSS) attacks
Output encoding ensures user input is treated as data, not executable code.
D
Preventing SQL injection attacks
Why wrong: SQL injection is prevented by parameterized queries, not output encoding.

Full breakdown with real-world context →

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

✓

Preventing cross-site scripting (XSS) attacks

Output encoding is the practice of converting special characters (e.g., <, >, &, ") into their corresponding HTML entities (e.g., < > & ") before sending data to the browser. This ensures that any user-supplied data is treated as text, not executable code, thereby neutralizing injected scripts. It is the primary defense against stored, reflected, and DOM-based cross-site scripting (XSS) attacks because it breaks the parser's ability to interpret the data as active content.

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.

✗
Preventing buffer overflow attacks
Why it's wrong here
Buffer overflows are prevented by proper memory management and bounds checking.
✗
Preventing cross-site request forgery (CSRF)
Why it's wrong here
CSRF is prevented by CSRF tokens, not output encoding.
✓
Preventing cross-site scripting (XSS) attacks
Why this is correct
Output encoding ensures user input is treated as data, not executable code.
Clue confirmation
The clue word "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Preventing SQL injection attacks
Why it's wrong here
SQL injection is prevented by parameterized queries, not output encoding.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates confuse output encoding with input validation or sanitization, mistakenly thinking it prevents SQL injection or CSRF, but output encoding only neutralizes XSS by ensuring data is rendered as text in the browser, not as executable code.

Trap categories for this question

Command / output trap
CSRF is prevented by CSRF tokens, not output encoding.

Detailed technical explanation

How to think about this question

Output encoding must be context-aware: encoding for HTML body (e.g., < for <) differs from encoding for JavaScript strings (e.g., \x3C for <) or CSS contexts (e.g., \3C). A common subtlety is double encoding—if the application decodes input before encoding output, an attacker can bypass filters by encoding payloads twice. In real-world frameworks like OWASP Java Encoder or Microsoft AntiXSS, the encoder automatically selects the correct encoding scheme based on the output context (HTML, attribute, URL, JavaScript).

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.

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FAQ

Questions learners often ask

What does this CISSP question test?

Software Development Security — This question tests Software Development Security — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Preventing cross-site scripting (XSS) attacks — Output encoding is the practice of converting special characters (e.g., <, >, &, ") into their corresponding HTML entities (e.g., < > & ") before sending data to the browser. This ensures that any user-supplied data is treated as text, not executable code, thereby neutralizing injected scripts. It is the primary defense against stored, reflected, and DOM-based cross-site scripting (XSS) attacks because it breaks the parser's ability to interpret the data as active content.

What should I do if I get this CISSP 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: "primary". Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jul 4, 2026

Question Discussion

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This CISSP 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 CISSP exam.