Computer Security 100 MCQs With Answer and Explanation

1. Computer security is mainly concerned with ________.
A) Protecting software from errors
B) Protecting data and systems from unauthorized access
C) Improving hardware performance
D) Reducing power consumption

2. The term “cybersecurity” refers to _________.
A) Hardware repair
B) Protection of Internet-connected systems
C) Software installation
D) Data compression

3. Which of the following is an example of malware?
A) Antivirus
B) Trojan horse
C) Firewall
D) Backup software

4. A program that hides inside another program and performs malicious actions is called _________.
A) Virus
B) Worm
C) Trojan horse
D) Spyware

5. Which malware spreads automatically without human intervention?
A) Trojan horse
B) Worm
C) Virus
D) Spyware

6. A program that infects other programs and spreads when the infected program is executed is called _________.
A) Virus
B) Worm
C) Trojan horse
D) Spyware

7. Ransomware is malware that _________.
A) Deletes all files
B) Encrypts files and demands payment for decryption
C) Slows down computer performance
D) Displays pop-up ads

8. Spyware is _________.
A) A protective software
B) Software that monitors user activities secretly
C) Cloud storage service
D) Internet browser

9. Adware primarily _________.
A) Deletes files
B) Displays unwanted advertisements
C) Encrypts data
D) Monitors network traffic

10. Which of the following is used to detect and remove malware?
A) Firewall
B) Antivirus software
C) Cloud storage
D) Proxy server

11. A firewall is used to _________.
A) Protect a network from unauthorized access
B) Increase Internet speed
C) Encrypt files
D) Store data online

12. A strong password should include _________.
A) Only lowercase letters
B) Letters, numbers, and special characters
C) Only numbers
D) Only uppercase letters

13. Two-factor authentication (2FA) enhances security by _________.
A) Using two passwords
B) Requiring a password and a second factor like OTP
C) Encrypting emails
D) Blocking malware

14. Phishing attacks are primarily aimed at _________.
A) Damaging hardware
B) Stealing sensitive information like passwords
C) Increasing bandwidth
D) Slowing down computers

15. A fake website that mimics a legitimate one to steal data is called _________.
A) Worm
B) Phishing site
C) Trojan horse
D) Ransomware

16. Man-in-the-middle (MITM) attack involves _________.
A) Encrypting files
B) Intercepting communication between two parties
C) Deleting files
D) Sending spam emails

17. Which of the following encrypts data for secure communication?
A) SSL/TLS
B) HTTP
C) FTP
D) SMTP

18. VPN stands for _________.
A) Virtual Private Network
B) Very Private Network
C) Virtual Protected Node
D) Verified Protocol Network

19. RDP (Remote Desktop Protocol) is used for _________.
A) Local file storage
B) Remote access to computers
C) Email transfer
D) Cloud backup

20. DDoS attacks aim to _________.
A) Steal passwords
B) Overwhelm a server with traffic, causing disruption
C) Encrypt files
D) Spy on users

21. Social engineering attacks exploit _________.
A) Software vulnerabilities
B) Human psychology
C) Network routers
D) Firewalls

22. CAPTCHA is used to _________.
A) Encrypt files
B) Prevent automated bot submissions
C) Improve bandwidth
D) Protect hardware

23. A digital certificate ensures _________.
A) Identity verification and secure communication
B) Faster Internet
C) Malware removal
D) Cloud storage access

24. Public key cryptography uses _________.
A) Single key for encryption and decryption
B) Two keys: public and private
C) Only passwords
D) Only symmetric keys

25. A honeypot in cybersecurity refers to _________.
A) A malware removal tool
B) A decoy system to attract attackers
C) Cloud storage solution
D) Firewall configuration

26. Antivirus software primarily works by _________.
A) Encrypting data
B) Detecting, quarantining, and removing malware
C) Blocking network traffic
D) Storing data in the cloud

27. Real-time protection in antivirus software means _________.
A) Scanning files only when executed
B) Continuous monitoring of the system for malware
C) Only updating virus definitions
D) Automatic backup

28. Which of the following is a common antivirus software?
A) Microsoft Word
B) Norton
C) Photoshop
D) Google Drive

29. A firewall can be _________.
A) Hardware only
B) Software only
C) Both hardware and software
D) Cloud service only

30. A packet filtering firewall works at which layer of the OSI model?
A) Application
B) Transport
C) Network
D) Data Link

31. Stateful inspection firewalls track _________.
A) Only packet headers
B) The state of active connections
C) Malware signatures
D) Encrypted traffic

32. Which of the following is a common backup strategy?
A) Full backup
B) Incremental backup
C) Differential backup
D) All of the above

33. A full backup _________.
A) Copies only changed files
B) Copies all selected files
C) Compresses data for storage
D) Encrypts files

34. Incremental backup saves _________.
A) All files every time
B) Only files changed since the last backup
C) Only system files
D) Only cloud files

35. Differential backup saves _________.
A) Only new files
B) All files changed since the last full backup
C) All system files
D) Cloud-based files only

36. Data encryption ensures _________.
A) Faster Internet
B) Confidentiality of information
C) Removal of viruses
D) Backup efficiency

37. Which encryption type uses the same key for encryption and decryption?
A) Asymmetric
B) Symmetric
C) Hashing
D) Blockchain

38. Which encryption type uses a public key and a private key?
A) Symmetric
B) Asymmetric
C) Hashing
D) SSL only

39. Backup storage can be _________.
A) External hard drives
B) Cloud storage
C) Network-attached storage
D) All of the above

40. Which type of backup is fastest to restore?
A) Incremental
B) Full
C) Differential
D) Random

41. Two-step verification improves security by _________.
A) Using stronger passwords only
B) Requiring a password and a secondary factor
C) Encrypting files automatically
D) Blocking all emails

42. Biometrics used for authentication include _________.
A) Fingerprints
B) Retina scan
C) Voice recognition
D) All of the above

43. A security policy is _________.
A) A set of rules to protect IT resources
B) Antivirus software
C) Firewall configuration only
D) Backup procedure

44. Patch management ensures _________.
A) Updating software to fix security vulnerabilities
B) Encrypting files
C) Creating backups
D) Increasing storage

45. Two types of firewalls are _________.
A) Packet filtering and proxy
B) Antivirus and spyware
C) Full and incremental
D) Hardware only

46. Endpoint security focuses on _________.
A) Servers only
B) Client devices like laptops and mobile phones
C) Cloud infrastructure only
D) Routers only

47. Intrusion Detection System (IDS) is used to _________.
A) Encrypt data
B) Monitor network for suspicious activities
C) Backup files
D) Block malware

48. Intrusion Prevention System (IPS) differs from IDS by _________.
A) Not detecting attacks
B) Actively blocking attacks
C) Slowing network traffic
D) Encrypting communications

49. Cloud backup provides _________.
A) On-site storage only
B) Remote storage accessible over Internet
C) Only incremental backup
D) Antivirus services

50. Security awareness training helps _________.
A) Improve firewall settings
B) Educate users on safe computing practices
C) Encrypt emails
D) Create backups

51. Advanced Persistent Threat (APT) refers to _________.
A) Temporary malware
B) Long-term, targeted cyberattack
C) Spam email attack
D) Denial-of-Service attack

52. Zero-day attack exploits _________.
A) Known vulnerabilities
B) Previously unknown vulnerabilities
C) Weak passwords
D) Network bandwidth

53. Keylogger is used to _________.
A) Encrypt files
B) Record keystrokes secretly
C) Block malware
D) Backup data

54. Botnet refers to _________.
A) A single malware program
B) Network of compromised computers controlled remotely
C) Firewall software
D) Encryption tool

55. SQL Injection attacks target _________.
A) Network hardware
B) Databases
C) Emails
D) Firewalls

56. Cross-Site Scripting (XSS) attacks target _________.
A) Websites and users through malicious scripts
B) Email servers
C) Firewalls
D) Backup files

57. Social engineering attacks primarily exploit _________.
A) Hardware flaws
B) Human behavior and trust
C) Encrypted communications
D) Cloud servers

58. Ethical hacking is _________.
A) Unauthorized hacking
B) Legal hacking to identify vulnerabilities
C) Malware development
D) Virus distribution

59. Penetration testing involves _________.
A) Encrypting files
B) Simulating attacks to test security
C) Blocking malware
D) Creating backups

60. White-hat hackers are _________.
A) Malicious hackers
B) Ethical hackers who help improve security
C) Spyware developers
D) Script kiddies

61. Black-hat hackers are _________.
A) Ethical hackers
B) Malicious hackers breaking into systems illegally
C) Network administrators
D) Antivirus developers

62. Gray-hat hackers are _________.
A) Always ethical
B) Hack without permission but without malicious intent
C) Cybersecurity professionals only
D) Botnet operators

63. Ransomware-as-a-Service (RaaS) refers to _________.
A) Free antivirus software
B) Subscription-based ransomware tools for attackers
C) Cloud storage service
D) Backup software

64. Phishing can be prevented by _________.
A) Using strong passwords
B) Verifying sender identity before clicking links
C) Updating antivirus
D) All of the above

65. Spear phishing targets _________.
A) Random users
B) Specific individuals or organizations
C) Network routers
D) Firewalls

66. Denial-of-Service (DoS) attacks aim to _________.
A) Encrypt data
B) Overwhelm systems to make services unavailable
C) Steal passwords
D) Update software

67. Distributed Denial-of-Service (DDoS) attacks use _________.
A) A single computer
B) Multiple compromised systems
C) Only mobile devices
D) Only cloud servers

68. Malware analysis is done to _________.
A) Create malware
B) Understand and mitigate malware behavior
C) Encrypt data
D) Backup files

69. Security Information and Event Management (SIEM) is used for _________.
A) Real-time monitoring and analysis of security events
B) Encrypting files
C) Backup management
D) Email filtering only

70. Honeypots are _________.
A) Antivirus software
B) Decoy systems to lure attackers
C) Cloud storage
D) Network routers

71. Key management in cryptography involves _________.
A) Storing passwords only
B) Generating, distributing, and managing encryption keys securely
C) Encrypting emails
D) Firewall configuration

72. Patch management helps in _________.
A) Fixing software vulnerabilities
B) Creating backups
C) Encrypting data
D) Blocking spam

73. Cybercrime includes _________.
A) Identity theft
B) Financial fraud
C) Malware attacks
D) All of the above

74. Ethical hackers use _________.
A) Unauthorized access techniques for malicious purposes
B) Hacking skills legally to secure systems
C) Malware development
D) Cloud storage

75. Bug bounty programs _________.
A) Offer rewards for finding software vulnerabilities
B) Provide antivirus services
C) Backup data online
D) Block phishing emails

76. Cloud security ensures _________.
A) Data stored in the cloud is protected from unauthorized access
B) Faster Internet
C) Malware removal on local systems only
D) Backup of physical devices

77. End-to-end encryption ensures _________.
A) Data is readable by intermediaries
B) Only sender and receiver can read the data
C) Data is compressed
D) Data is backed up automatically

78. Multi-factor authentication (MFA) requires _________.
A) Only a password
B) Multiple forms of verification
C) Only a security question
D) Only biometrics

79. Tokenization in security is used for _________.
A) Replacing sensitive data with non-sensitive tokens
B) Encrypting files with a password
C) Blocking malware
D) Storing files in cloud

80. Blockchain technology enhances security by _________.
A) Encrypting emails only
B) Providing immutable, decentralized records
C) Faster Internet
D) Data compression

81. IoT security focuses on _________.
A) Securing devices connected to the Internet
B) Encrypting cloud files only
C) Firewall for laptops only
D) Antivirus installation

82. Common IoT security risks include _________.
A) Device hijacking
B) Data leaks
C) Botnet attacks
D) All of the above

83. Zero Trust Security model means _________.
A) Trust all devices inside a network
B) Never trust, always verify every access request
C) Encrypt only passwords
D) Only use cloud backup

84. AI in cybersecurity helps to _________.
A) Predict and detect threats automatically
B) Encrypt files only
C) Backup data automatically
D) Install firewalls

85. Security Information and Event Management (SIEM) systems provide _________.
A) Real-time monitoring and analysis of security alerts
B) Only data encryption
C) Malware removal
D) Cloud storage

86. Cloud Access Security Broker (CASB) is used for _________.
A) Monitoring cloud usage and enforcing security policies
B) Encrypting emails only
C) Backup management
D) Blocking viruses locally

87. Role-based access control (RBAC) allows _________.
A) Everyone to access all resources
B) Assigning permissions based on user roles
C) Encrypting all files automatically
D) Firewall configuration only

88. Security patches in cloud environments help to _________.
A) Reduce security vulnerabilities
B) Encrypt files
C) Backup data
D) Block phishing emails

89. API security is important because _________.
A) APIs transfer data between services and can be exploited if insecure
B) Only encrypts emails
C) Provides backup
D) Blocks malware on servers

90. Edge computing security ensures _________.
A) Data is processed and secured near the source
B) All data stored only in cloud
C) Local antivirus installation
D) Firewall configuration only

91. Distributed Ledger Technology (DLT) ensures _________.
A) Centralized storage
B) Tamper-proof, decentralized record keeping
C) Data compression
D) Cloud backup

92. Quantum cryptography provides _________.
A) Faster Internet
B) Encryption based on quantum mechanics principles
C) Cloud storage
D) Antivirus protection

93. Cloud-native security integrates _________.
A) Security into cloud applications from development stage
B) Only firewalls
C) Antivirus software only
D) Backup services only

94. Security orchestration, automation, and response (SOAR) systems _________.
A) Automate threat detection and response
B) Only encrypt files
C) Provide cloud storage
D) Only perform backups

95. Multi-cloud security deals with _________.
A) Security across multiple cloud service providers
B) Only on-premise networks
C) Local antivirus updates
D) Firewall monitoring

96. Firmware updates in IoT devices are important because _________.
A) They improve battery life only
B) They fix security vulnerabilities and bugs
C) Only increase device speed
D) Backup device data

97. Secure coding practices help to _________.
A) Prevent vulnerabilities during software development
B) Backup cloud data
C) Encrypt emails only
D) Monitor network traffic

98. Cyber threat intelligence (CTI) provides _________.
A) Data about potential cyber threats for proactive defense
B) Antivirus scanning
C) Cloud backup
D) Network acceleration

99. Mobile device management (MDM) ensures _________.
A) Security, configuration, and monitoring of mobile devices
B) Only cloud backups
C) Antivirus installation
D) Firewall configuration

100. Zero Trust Network Access (ZTNA) differs from traditional VPN by _________.
A) Allowing unrestricted access
B) Granting access based on identity, device, and context
C) Encrypting only emails
D) Blocking all cloud access