This FC0-U61 practice question tests your understanding of database fundamentals. 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.
A web application constructs SQL queries by concatenating user input directly. What is the primary security risk?
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.
SQL injection
Input concatenation allows malicious SQL execution.
Denial of service
Why wrong: DoS is possible but not the primary risk.
Cross-site scripting
Why wrong: XSS involves injecting scripts into web pages.
Buffer overflow
Why wrong: Not directly related to SQL.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
SQL injection
When a web application constructs SQL queries by concatenating user input directly, an attacker can inject malicious SQL code into the query. This allows the attacker to manipulate the database, such as by bypassing authentication, retrieving unauthorized data, or executing arbitrary commands. This is the classic definition of SQL injection, which exploits the lack of input sanitization or parameterized queries.
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.
SQL injection
Why this is correct
Input concatenation allows malicious SQL execution.
Clue confirmation
The clue word "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Denial of service
Why it's wrong here
DoS is possible but not the primary risk.
Cross-site scripting
Why it's wrong here
XSS involves injecting scripts into web pages.
Buffer overflow
Why it's wrong here
Not directly related to SQL.
Common exam traps
The trap here is that candidates may confuse SQL injection with cross-site scripting (XSS) because both involve user input, but XSS targets the browser with scripts, while SQL injection targets the database server directly.
Detailed technical explanation
Under the hood, SQL injection works by breaking out of the intended SQL string context using characters like a single quote (') or a double dash (--) to comment out the rest of the query. For example, inputting ' OR '1'='1 into a login field can turn a SELECT statement into one that always returns true, bypassing authentication. In real-world scenarios, tools like sqlmap automate the exploitation, and defenses include prepared statements (parameterized queries) and stored procedures, which separate SQL logic from data.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
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FAQ
Database Fundamentals — This question tests Database Fundamentals — Read the scenario before looking for a memorised answer..
The correct answer is: SQL injection — When a web application constructs SQL queries by concatenating user input directly, an attacker can inject malicious SQL code into the query. This allows the attacker to manipulate the database, such as by bypassing authentication, retrieving unauthorized data, or executing arbitrary commands. This is the classic definition of SQL injection, which exploits the lack of input sanitization or parameterized queries.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "primary". Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 25, 2026
This FC0-U61 practice question is part of Courseiva's free CompTIA 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 FC0-U61 exam.
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