Introduction
Class 7 Computer Security MCQs with Solutions is specially designed to help students understand the basics of cyber safety and online protection in a simple and exam-friendly way. This post includes carefully selected multiple-choice questions with clear and detailed explanations to strengthen students’ concepts. These MCQs cover important topics like passwords, viruses, phishing, malware, and safe internet practices.
Practicing these questions improves confidence, boosts exam performance, and develops awareness about digital security. Each solution explains the correct answer in an easy language so students can avoid common mistakes. This resource is highly useful for school exams, class tests, and competitive preparation.
Computer Security MCQ
Master computer security concepts with 60 unique multiple-choice questions covering threats, viruses, firewalls, cybercrime, and ethics.
0 / 60 answered
Section 1
Introduction, Threats & Computer Viruses
Q1 – Q20Q1
What is computer security primarily concerned with?
✅ Correct Answer: B. Computer security involves protecting computer systems, networks, and data from digital attacks, unauthorized access, damage, or theft. It ensures the confidentiality, integrity, and availability of information stored on or transmitted through computing systems.
Q2
Which of the following best defines a “threat” in computer security?
✅ Correct Answer: B. In computer security, a threat is any potential danger that could exploit a system’s vulnerability. Threats can be natural (floods, fires), accidental (user errors), or intentional (hackers, malware) and can compromise data security, system availability, or data integrity.
Q3
Which of the following is NOT a common computer threat?
✅ Correct Answer: C. Disk defragmentation is a maintenance process that reorganizes fragmented data on a hard drive to improve performance — it is a beneficial operation, not a threat. Common computer threats include malware, phishing, unauthorized access, denial-of-service attacks, and data breaches.
Q4
What is a computer virus?
✅ Correct Answer: C. A computer virus is malicious software (malware) that attaches itself to legitimate programs or files. When an infected file runs, the virus replicates and spreads to other files. Viruses can corrupt data, slow performance, delete files, or allow hackers to gain unauthorized access.
Q5
How does a computer virus primarily spread from one system to another?
✅ Correct Answer: B. Computer viruses spread through multiple channels including infected email attachments, malicious downloads from the internet, infected USB drives or CDs, file sharing networks, and visiting compromised websites. The virus activates when the infected file or program is opened or executed.
Q6
A Boot Sector Virus infects which part of a computer?
✅ Correct Answer: B. A Boot Sector Virus targets the master boot record (MBR) or the boot sector of hard drives and storage devices. Since the boot sector loads before the operating system, this virus executes before any security software runs, making it particularly difficult to detect and remove effectively.
Q7
Which type of virus specifically targets executable program files with extensions like .exe or .com?
✅ Correct Answer: C. A File Virus (also called a program virus) attaches itself to executable files such as .exe, .com, .sys, or .bat files. When a user runs the infected program, the virus activates, spreads to other executable files on the system, and can cause data loss or system damage.
Q8
A Macro Virus most commonly infects which type of files?
✅ Correct Answer: C. Macro Viruses embed malicious code within macros of document files, most commonly Microsoft Word (.doc) and Excel (.xls) files. When a user opens an infected document and enables macros, the virus executes, can spread to other documents, corrupt data, or download additional malware.
Q9
What is the key characteristic that distinguishes a Worm from a traditional virus?
✅ Correct Answer: B. Unlike traditional viruses that need a host file to spread, worms are standalone malicious programs that replicate independently across networks without human interaction. Worms consume network bandwidth, can carry payloads, delete files, and open backdoors for remote attackers to exploit.
Q10
A Trojan Horse differs from a virus because it:
✅ Correct Answer: B. A Trojan Horse masquerades as a legitimate, helpful application to trick users into downloading and running it. Unlike viruses, Trojans do not self-replicate. Once installed, they can steal data, create backdoors, log keystrokes, download more malware, and give attackers remote control of the infected system.
Q11
Which sign most likely indicates a computer has been infected by a virus?
✅ Correct Answer: C. Common symptoms of a virus-infected computer include sudden and unexplained performance slowdowns, programs crashing unexpectedly, files mysteriously disappearing or becoming corrupted, excessive hard drive activity, unfamiliar programs starting automatically, and strange pop-up messages appearing on screen.
Q12
Which of the following actions is most likely to introduce a virus into a computer?
✅ Correct Answer: B. Opening email attachments from unknown or suspicious senders is one of the most common ways viruses enter a computer. Cybercriminals disguise malware as innocent-looking files (PDFs, images, Word docs) and use social engineering tactics to lure unsuspecting users into opening them.
Q13
What is “social engineering” in the context of computer security?
✅ Correct Answer: B. Social engineering exploits human psychology rather than technical vulnerabilities. Attackers manipulate people into divulging passwords, clicking malicious links, or granting access by impersonating trusted entities. Common examples include phishing emails, pretexting phone calls, and baiting attacks that exploit trust.
Q14
Which of the following BEST describes “phishing”?
✅ Correct Answer: B. Phishing is a deceptive cybercrime where attackers impersonate legitimate organizations (banks, tech companies, government agencies) via email, text, or fake websites to trick victims into revealing sensitive information such as passwords, credit card numbers, or social security numbers.
Q15
What does “malware” stand for?
✅ Correct Answer: B. Malware is a portmanteau (combined word) of “malicious software.” It is an umbrella term covering any software specifically designed to disrupt, damage, or gain unauthorized access to computer systems. Malware includes viruses, worms, Trojan horses, ransomware, spyware, adware, and rootkits.
Q16
Ransomware is a type of malware that:
✅ Correct Answer: B. Ransomware encrypts the victim’s files or locks their system and demands a ransom payment (usually cryptocurrency) in exchange for the decryption key. High-profile ransomware attacks have targeted hospitals, corporations, and government agencies, causing billions of dollars in damages worldwide each year.
Q17
What type of malware secretly records everything a user types, including passwords?
✅ Correct Answer: B. A keylogger is malicious software that silently records every keystroke a user makes on their keyboard, capturing passwords, credit card numbers, private messages, and other sensitive data. The collected information is then secretly transmitted to the attacker for identity theft or unauthorized access to accounts.
Q18
Which of these represents a strong password practice?
✅ Correct Answer: C. A strong password combines uppercase letters, lowercase letters, numbers, and special symbols and is at least 12–16 characters long. Strong passwords are difficult to guess or crack through brute force attacks. Users should also use unique passwords for every account to limit the damage if one password is compromised.
Q19
What is a “zero-day vulnerability”?
✅ Correct Answer: B. A zero-day vulnerability is a software security flaw that is unknown to the software vendor and therefore has no patch or fix available. Attackers exploit zero-day vulnerabilities before developers become aware of them. The term “zero-day” refers to the fact that developers have had zero days to address the flaw.
Q20
Which method does a worm use to spread across a network without human interaction?
✅ Correct Answer: B. Worms actively scan networks for vulnerable systems and exploit security weaknesses to automatically replicate and install themselves on new machines without any user action. Famous worms like WannaCry and ILOVEYOU spread to millions of computers in days, causing enormous data loss and financial damage globally.
Section 2
Antivirus Software & Firewalls
Q21 – Q40Q21
What is the primary purpose of antivirus software?
✅ Correct Answer: B. Antivirus software is a security program designed to detect, prevent, quarantine, and remove malicious software including viruses, worms, Trojans, spyware, and ransomware. It works by scanning files against a database of known malware signatures and using heuristic analysis to identify new, unknown threats.
Q22
Which of the following is a well-known antivirus software?
✅ Correct Answer: B. Norton Antivirus is one of the most widely recognized and used antivirus software products in the world, developed by NortonLifeLock. Other popular antivirus products include McAfee, Kaspersky, Avast, Bitdefender, AVG, and Windows Defender which is built into modern Windows operating systems.
Q23
Why is it important to regularly update antivirus software?
✅ Correct Answer: B. New malware threats emerge every day, so antivirus software must regularly update its virus definition database to recognize and block the latest threats. Outdated antivirus software cannot detect newly created viruses, leaving the computer vulnerable. Updates also include improved detection algorithms and security patches for the antivirus program itself.
Q24
What is “real-time protection” in antivirus software?
✅ Correct Answer: B. Real-time protection (also called on-access scanning) continuously monitors all file activity, downloads, and running processes in the background. It intercepts and scans files when they are accessed, opened, or created, blocking threats immediately before they can execute and harm the system rather than finding infections after they occur.
Q25
What is a firewall in computer security?
✅ Correct Answer: B. A firewall is a network security system (either hardware, software, or both) that monitors and filters incoming and outgoing network traffic based on predetermined security rules. It creates a protective barrier between a trusted internal network and untrusted external networks like the internet, blocking unauthorized access.
Q26
A packet filtering firewall examines network data based on which criteria?
✅ Correct Answer: B. Packet filtering firewalls inspect each data packet’s header information including source IP address, destination IP address, source port, destination port, and network protocol (TCP/UDP). Based on predefined rules, the firewall either allows or blocks each packet without inspecting the actual content of the data payload.
Q27
Which type of firewall operates at the application layer and can inspect the actual content of data packets?
✅ Correct Answer: B. An application-layer or proxy firewall operates at the highest level of the OSI model. It acts as a proxy between users and the internet, fully inspecting data packet content, application protocols, and user behavior. This deep inspection allows it to detect sophisticated threats hidden within seemingly legitimate traffic that simpler firewalls miss.
Q28
What is the main advantage of using a hardware firewall over a software firewall?
✅ Correct Answer: B. Hardware firewalls are dedicated physical devices installed between a network and its internet connection. They protect all devices on the network simultaneously without using any individual computer’s CPU or memory resources. This makes them ideal for businesses where protecting multiple computers from a single point is critical for network security.
Q29
What does “quarantine” mean in the context of antivirus software?
✅ Correct Answer: B. Quarantine in antivirus software means moving a suspicious or infected file to a special isolated folder where it cannot execute, access the file system, or spread to other files. The quarantined file remains on the system, allowing the user or antivirus to further analyze it, restore it if it was a false positive, or delete it permanently.
Q30
What is “heuristic analysis” in antivirus software?
✅ Correct Answer: B. Heuristic analysis enables antivirus software to detect new or previously unknown malware by examining the code and behavior of programs for suspicious patterns or actions — such as attempting to modify system files, replicate themselves, or communicate with unknown servers — rather than relying solely on a database of known virus signatures.
Q31
Which of the following is a use of a firewall?
✅ Correct Answer: B. One of the primary uses of a firewall is to block unauthorized remote access attempts to a private network. Firewalls enforce security rules that prevent hackers from establishing unauthorized connections, protect sensitive internal resources from external threats, and ensure only legitimate, authorized traffic enters or leaves the network.
Q32
What is a “false positive” in antivirus scanning?
✅ Correct Answer: B. A false positive occurs when antivirus software incorrectly flags a legitimate, harmless file or program as malicious. This can happen due to similarity to known malware patterns or overly aggressive heuristic detection. False positives can lead to important system files being quarantined or deleted, potentially causing software or system failures.
Q33
What does a firewall use to decide which network traffic to allow or block?
✅ Correct Answer: B. Firewalls operate based on a set of predefined security rules and access control policies configured by network administrators. These rules define which types of traffic, IP addresses, ports, and protocols are permitted or denied. Traffic that matches an “allow” rule passes through; traffic that matches a “deny” rule or has no matching rule is blocked.
Q34
Windows Defender is an example of which type of security tool?
✅ Correct Answer: B. Windows Defender (now called Microsoft Defender Antivirus) is a free, built-in antivirus and anti-malware program that comes pre-installed with Windows 8 and later versions. It provides real-time protection, cloud-based threat detection, firewall management, and periodic system scanning without requiring any additional software installation.
Q35
What is a “DMZ” (Demilitarized Zone) in network security?
✅ Correct Answer: B. A DMZ (Demilitarized Zone) is a physical or logical network segment that separates an organization’s internal network from the internet. Public-facing servers (web, email, DNS) are placed in the DMZ, where they can be accessed externally while being isolated from the sensitive internal network, limiting the damage if they are compromised.
Q36
Which antivirus feature scans files only when they are accessed or executed?
✅ Correct Answer: C. On-access scanning (real-time protection) automatically checks files for malware at the moment they are accessed, opened, copied, or executed. This approach provides continuous, immediate protection and stops threats before they activate. It differs from on-demand scans which only run when manually triggered or scheduled by the user.
Q37
What is the role of antivirus software’s “virus definition database”?
✅ Correct Answer: B. A virus definition database (also called a signature database) is a continuously updated library of digital fingerprints of known malware. When antivirus software scans a file, it compares the file’s code patterns against these signatures. A match indicates the presence of a known threat. Regular updates ensure the database includes the newest discovered malware signatures.
Q38
A firewall that tracks the state of active network connections is called a:
✅ Correct Answer: B. A stateful inspection firewall monitors the complete state of active network connections by tracking which connections are established, ongoing, or closing. Unlike simple packet filtering, it evaluates packets in the context of the entire connection, making it significantly more effective at detecting and blocking suspicious traffic patterns and session-hijacking attacks.
Q39
Which of the following best describes McAfee?
✅ Correct Answer: B. McAfee is one of the world’s largest cybersecurity software companies, offering antivirus, internet security, and endpoint protection products for both consumers and businesses. Founded by John McAfee in 1987, it provides real-time threat detection, firewall protection, identity monitoring, and safe web browsing features to millions of users worldwide.
Q40
What happens when a firewall receives a packet that does not match any rule?
✅ Correct Answer: B. Most firewalls follow a “default deny” security principle, meaning any network traffic that does not match an explicitly defined “allow” rule is automatically blocked and dropped. This conservative approach ensures that unknown or suspicious traffic is rejected by default, reducing the attack surface and preventing unauthorized access through unspecified channels.
Section 3
Cybercrime & Computer Ethics
Q41 – Q60Q41
What is cybercrime?
✅ Correct Answer: B. Cybercrime encompasses any criminal activity that involves a computer, network, or internet-connected device either as the tool used to commit the crime or as the target of the crime. Examples include hacking, identity theft, online fraud, cyberstalking, distribution of child exploitation material, and ransomware attacks.
Q42
What is “identity theft” in the context of cybercrime?
✅ Correct Answer: B. Identity theft is a serious crime where a criminal steals a person’s personal information — such as name, social security number, credit card details, or passwords — and uses it fraudulently to open bank accounts, apply for loans, make purchases, or commit other crimes while impersonating the victim, causing significant financial and reputational damage.
Q43
A Denial-of-Service (DoS) attack aims to:
✅ Correct Answer: B. A Denial-of-Service (DoS) attack floods a target server, website, or network with an overwhelming amount of traffic or requests, exhausting its resources and making it slow or completely unavailable to legitimate users. Distributed DoS (DDoS) attacks use thousands of compromised computers simultaneously to launch even more powerful attacks.
Q44
What is “hacking” in computer security?
✅ Correct Answer: B. Hacking refers to identifying and exploiting weaknesses in a computer system or network to gain unauthorized access. While malicious hackers (black hats) commit cybercrime, ethical hackers (white hats) are authorized security professionals who use the same techniques to identify vulnerabilities so organizations can fix them before criminals exploit them.
Q45
What is cyberstalking?
✅ Correct Answer: B. Cyberstalking is a form of online harassment where a perpetrator uses electronic communications — email, social media, messaging apps, tracking software — to repeatedly and intentionally harass, intimidate, threaten, or monitor a victim. It is a criminal offense in most jurisdictions and can cause serious psychological harm to victims.
Q46
Software piracy is best described as:
✅ Correct Answer: B. Software piracy is the illegal reproduction, distribution, or use of copyrighted software without proper licensing or authorization from the copyright holder. It includes activities like sharing activation keys, distributing cracked software, and downloading paid programs from unauthorized sources. Software piracy costs the software industry billions of dollars annually and is a criminal offense.
Q47
What is computer ethics?
✅ Correct Answer: B. Computer ethics is a branch of applied ethics that examines moral questions arising from the development, deployment, and use of computer technology. It guides individuals and organizations on responsible behavior including respecting privacy, protecting intellectual property, avoiding harm, ensuring data accuracy, and maintaining fair access to technology and information.
Q48
Which of the following represents an important computer ethics principle?
✅ Correct Answer: B. Respecting privacy is a fundamental principle of computer ethics. Users and organizations must treat personal and confidential digital information with care and discretion. This means not sharing private data without consent, not reading others’ private messages, securing sensitive data with appropriate protections, and following data protection laws and regulations.
Q49
What does “data privacy” mean in the context of computer use?
✅ Correct Answer: B. Data privacy refers to individuals’ fundamental right to determine who collects their personal information, how it is used, how long it is stored, and who it is shared with. Organizations are ethically and legally obligated to handle personal data responsibly, transparently, and in accordance with relevant data protection legislation such as GDPR.
Q50
What is “online fraud”?
✅ Correct Answer: B. Online fraud involves using the internet or digital technology to deceive victims for financial gain or other illegal purposes. Common forms include fake online stores that take payment without delivering goods, advance-fee scams (“Nigerian prince” scams), investment fraud, auction fraud, and fraudulent job postings that steal personal information or money from applicants.
Q51
What is the ethical responsibility of a computer professional regarding system vulnerabilities?
✅ Correct Answer: B. Computer security professionals follow responsible disclosure practices: reporting discovered vulnerabilities to the affected organization privately, giving them reasonable time to develop and release a patch, and only then disclosing the details publicly if necessary. This ethical approach protects users while ensuring vendors address security issues promptly and properly.
Q52
What does “intellectual property” mean in a digital context?
✅ Correct Answer: B. Intellectual property in the digital world refers to original creative works — software code, digital artwork, music, videos, written content, and inventions — that are legally protected by copyright, patents, or trademarks. Ethically and legally, users must respect these rights by not copying, distributing, or modifying protected digital content without permission.
Q53
What is the “digital divide”?
✅ Correct Answer: B. The digital divide describes the socioeconomic gap between individuals, communities, and countries that have meaningful access to modern information and communication technology and those that do not. This inequality affects educational opportunities, economic participation, and quality of life. Computer ethics principles advocate for equitable and fair access to technology for all people.
Q54
Which practice demonstrates ethical behavior when using computers at work?
✅ Correct Answer: B. Ethical computer use in the workplace means using organizational IT resources strictly for authorized purposes, following acceptable use policies, protecting confidential information, not installing unapproved software that could introduce security risks, reporting security incidents promptly, and respecting the privacy of colleagues’ digital communications and personal data.
Q55
What is “cyberbullying”?
✅ Correct Answer: B. Cyberbullying involves using digital devices and online platforms — social media, text messages, gaming networks, or email — to repeatedly bully, harass, threaten, humiliate, or spread malicious content about someone. It is particularly harmful to young people and can cause serious psychological distress, depression, and in extreme cases, has contributed to suicide.
Q56
What does “responsible use of AI” require from users and developers?
✅ Correct Answer: B. Responsible AI use requires developers and users to ensure AI systems operate transparently, avoid bias and discrimination, maintain human oversight, protect privacy, and prioritize safety. Ethical AI frameworks require that these systems benefit society, clearly disclose their limitations, and include mechanisms for accountability when AI decisions cause harm or unfair outcomes.
Q57
What is “encryption” and why is it important for computer security?
✅ Correct Answer: B. Encryption transforms readable data (plaintext) into an unreadable scrambled format (ciphertext) using mathematical algorithms. Only someone with the correct decryption key can convert it back to readable form. Encryption protects sensitive data during storage and transmission, ensuring that even if data is intercepted or stolen, attackers cannot read its contents without the key.
Q58
What is two-factor authentication (2FA)?
✅ Correct Answer: B. Two-factor authentication (2FA) adds a second layer of security beyond just a password. After entering the correct password, users must also provide a second verification form — such as a one-time code sent via SMS, an authenticator app code, a fingerprint, or a hardware token. Even if a password is stolen, 2FA prevents unauthorized account access.
Q59
What does the principle of “least privilege” in computer security mean?
✅ Correct Answer: B. The principle of least privilege is a cybersecurity best practice where every user, program, and system component is granted only the minimum level of access rights and permissions needed to perform its intended function. This limits the potential damage from accidental errors, insider threats, or compromised accounts by preventing unnecessary access to sensitive resources.
Q60
Which of the following best describes a “data breach”?
✅ Correct Answer: B. A data breach is a security incident where sensitive, protected, or confidential data is accessed, stolen, or disclosed by unauthorized individuals. Breaches can result from hacking, malware, phishing, insider threats, or accidental exposure. Consequences include identity theft, financial losses, reputational damage, and significant legal penalties under data protection regulations.