The answer is blind (inferential) SQL injection, which includes both boolean-based and time-based variants. These are correct because they allow an attacker to extract information from a database without seeing direct error messages or data output; instead, the attacker infers truth values from changes in application behavior—such as a true/false response in boolean-based SQLi or a delay in server response in time-based SQLi. On the Certified Ethical Hacker CEH exam, this question tests your understanding of how SQL injection attacks are categorized, often appearing alongside in-band SQLi and out-of-band SQLi as the three main types. A common trap is confusing blind SQLi with out-of-band SQLi, but remember that blind SQLi relies on the same communication channel for inference, while out-of-band uses a separate channel like DNS or HTTP. For the exam, a helpful memory tip is: “Blind means no direct sight—you feel the truth through behavior or time.”
CEH Web Application and Injection Attacks Practice Question
This CEH practice question tests your understanding of web application and injection attacks. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 THREE of the following are types of SQL injection attacks? (Choose 3)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Out-of-band SQLi (e.g., DNS or HTTP exfiltration)
Out-of-band SQLi (option A) is correct because it uses a different channel (e.g., DNS or HTTP requests) to exfiltrate data when the attacker cannot receive direct responses from the database. This technique is effective when the database server can initiate outbound network connections, allowing data to be sent to an attacker-controlled server via DNS queries or HTTP requests.
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.
✓
Out-of-band SQLi (e.g., DNS or HTTP exfiltration)
Why this is correct
Out-of-band uses a different channel (e.g., DNS) to receive data.
Related concept
Read the scenario before looking for a memorised answer.
✗
Stored SQLi
Why it's wrong here
Stored is a term for XSS; SQLi is categorized differently.
✓
In-band SQLi (error-based or union-based)
Why this is correct
In-band uses the same channel to launch attack and gather results.
Related concept
Read the scenario before looking for a memorised answer.
✓
Blind (inferential) SQLi (boolean- or time-based)
Why this is correct
Blind SQLi does not directly display data; attacker infers based on responses or timing.
Related concept
Read the scenario before looking for a memorised answer.
✗
Reflected SQLi
Why it's wrong here
Reflected is a term for XSS, not SQLi.
Common exam traps
Common exam trap: answer the scenario, not the keyword
EC-Council often tests candidates by mixing SQL injection categories with XSS terminology (stored/reflected) to see if they confuse web attack types; the trap here is that 'stored' and 'reflected' are not SQLi types but XSS variants.
Detailed technical explanation
How to think about this question
In-band SQLi (option C) uses the same channel for attack and data retrieval, such as error messages (error-based) or UNION queries (union-based). Blind SQLi (option D) infers data by observing boolean responses or time delays (e.g., using `SLEEP()` in MySQL). Out-of-band SQLi (option A) relies on database features like `xp_cmdshell` in SQL Server or `UTL_HTTP` in Oracle to send data via DNS or HTTP, which is useful when the web application filters direct output but allows outbound traffic.
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 practitioner preparing for the CEH exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CEH question in full detail.
Web Application and Injection Attacks — This question tests Web Application and Injection Attacks — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Out-of-band SQLi (e.g., DNS or HTTP exfiltration) — Out-of-band SQLi (option A) is correct because it uses a different channel (e.g., DNS or HTTP requests) to exfiltrate data when the attacker cannot receive direct responses from the database. This technique is effective when the database server can initiate outbound network connections, allowing data to be sent to an attacker-controlled server via DNS queries or HTTP requests.
What should I do if I get this CEH question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which THREE of the following are common types of SQL injection attacks? (Select three)
medium
A.Reflected SQL injection
B.Stored SQL injection
✓ C.Out-of-band SQL injection
✓ D.Blind SQL injection
✓ E.In-band SQL injection
Why C: In-band SQL injection (including error-based and union-based) are classic types. Blind SQL injection (boolean-based and time-based) are also common. Out-of-band is less common but still a type.
Variation 2. Which TWO of the following are common types of SQL injection attacks?
easy
✓ A.Blind SQL injection (boolean-based)
B.Out-of-band SQL injection
✓ C.In-band SQL injection (union-based)
D.Heap-based SQL injection
E.NoSQL injection
Why A: In-band SQLi (union-based) uses the same channel to inject and retrieve data. Blind SQLi (boolean-based or time-based) does not return data directly but infers information from behavior. NoSQL injection is a separate category. Heap-based is not a recognized SQLi type. Out-of-band is a third type but not listed among the options; the question asks for common types.
Last reviewed: Jun 30, 2026
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This CEH practice question is part of Courseiva's free EC-Council 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 CEH exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.