Advanced Security MCQs

1. A backdoor in a cryptographic system is:

a) A secret method to bypass security mechanisms b) A secure login portal c) A type of virus scanner d) An encrypted password file

Correct Answer: a) A secret method to bypass security mechanisms

Explanation:
A backdoor is a hidden entry point that bypasses normal authentication procedures, often intentionally created but potentially exploited by attackers.

2. Trapdoors are often introduced by:

a) Developers for debugging but exploited by attackers b) Antivirus software c) Firewall rules d) Operating system updates

Correct Answer: a) Developers for debugging but exploited by attackers

Explanation:
Developers may leave trapdoors for legitimate debugging purposes, but these become security vulnerabilities if discovered and exploited by malicious actors.

3. Which of the following is a real-world example of a backdoor?

a) Dual_EC_DRBG (NSA's cryptographic backdoor) b) AES Encryption c) SHA-256 Hashing d) SSL/TLS Handshake

Correct Answer: a) Dual_EC_DRBG (NSA's cryptographic backdoor)

Explanation:
Dual_EC_DRBG was a pseudorandom number generator with a suspected NSA backdoor, allowing potential decryption of communications using a secret key.

4. How can backdoors be prevented?

a) Code audits and secure development practices b) Using weak passwords c) Disabling firewalls d) Ignoring software updates

Correct Answer: a) Code audits and secure development practices

Explanation:
Prevention methods include: rigorous code reviews, secure coding standards, removing debugging code before production, and using checksums to detect modifications.

5. DNS Cache Poisoning redirects users to fake websites by:

a) Modifying DNS resolver cache with false entries b) Encrypting DNS queries c) Disabling the DNS server d) Using strong passwords

Correct Answer: a) Modifying DNS resolver cache with false entries

Explanation:
Attackers inject fraudulent DNS records into resolver caches, causing domain names to resolve to malicious IP addresses instead of legitimate ones.

6. ARP Cache Poisoning is used in:

a) Man-in-the-Middle (MITM) attacks b) SQL Injection c) Phishing Emails d) DDoS Attacks

Correct Answer: a) Man-in-the-Middle (MITM) attacks

Explanation:
ARP poisoning associates the attacker's MAC address with the IP address of another host, intercepting network traffic intended for that host.

7. Which attack exploits the trust between a client and server by hijacking a session?

a) Session Hijacking b) Buffer Overflow c) Cross-Site Request Forgery (CSRF) d) Brute Force Attack

Correct Answer: a) Session Hijacking

Explanation:
Session hijacking involves stealing or predicting session tokens to impersonate legitimate users and gain unauthorized access to systems.

8. A zero-day exploit refers to:

a) A vulnerability unknown to the vendor, with no patch available b) An attack at midnight c) A type of firewall d) A secure encryption method

Correct Answer: a) A vulnerability unknown to the vendor, with no patch available

Explanation:
Zero-day exploits target undisclosed vulnerabilities, giving developers "zero days" to fix them before attacks occur, making them particularly dangerous.

9. Which of the following is a preventive measure against security vulnerabilities?

a) Regular software updates and patches b) Using default passwords c) Disabling encryption d) Ignoring intrusion detection systems

Correct Answer: a) Regular software updates and patches

Explanation:
Timely patching closes known vulnerabilities. Other preventive measures include: secure coding, least privilege, defense in depth, and security awareness training.

10. The principle of least privilege means:

a) Users/programs get minimal access needed b) Everyone has admin rights c) No authentication is required d) All files are publicly accessible

Correct Answer: a) Users/programs get minimal access needed

Explanation:
Least privilege limits damage from accidents or attacks by ensuring entities operate with only the permissions essential for their legitimate purpose.

11. Which attack floods a network with excessive requests to disrupt services?

a) Denial-of-Service (DoS) Attack b) Phishing Attack c) SQL Injection d) Cross-Site Scripting (XSS)

Correct Answer: a) Denial-of-Service (DoS) Attack

Explanation:
DoS attacks overwhelm systems with traffic (e.g., SYN floods) to make resources unavailable. DDoS uses multiple compromised systems for larger-scale attacks.

12. An example of a non-technical security threat is:

a) Social Engineering (e.g., phishing) b) Buffer Overflow c) SQL Injection d) Cross-Site Request Forgery (CSRF)

Correct Answer: a) Social Engineering (e.g., phishing)

Explanation:
Social engineering manipulates human psychology rather than exploiting technical vulnerabilities. Examples include phishing, pretexting, baiting, and tailgating.

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