Top Cyber Security Interview Questions and Answers

What is Cyber Security?

Cybersecurity is the practice of protecting computer systems, networks, and data from unauthorized access, use, disclosure, disruption, modification, or destruction. It involves a wide range of technologies, processes, and practices to mitigate risks and threats in the digital world.

Cybercrime Examples

  • Identity theft
  • Online scams and fraud
  • Data breaches
  • Ransomware attacks
  • Phishing
  • Hacking

Reasons for the Rise in Cybercrime

  • Relatively easy to commit.
  • Low risk of apprehension.
  • High potential financial rewards.
  • Ability to target many victims simultaneously.
  • Increased opportunities due to the growth of online transactions and digital assets.

Main Goals of Cyber Security

The primary goal of cybersecurity is to protect data confidentiality, integrity, and availability (CIA triad). This model provides a framework for implementing security measures and managing risks.

CIA Triad

Confidentiality Integrity Availability
Protecting data from unauthorized access. Ensuring data accuracy and preventing unauthorized modification. Ensuring that data and systems are accessible to authorized users when needed.

Advantages of Cyber Security

  • Protection against financial losses from cyberattacks.
  • Safeguarding sensitive user data.
  • Improved data and network security.
  • Reduced recovery time after a security breach.
  • Enhanced reputation and customer trust.

IDS (Intrusion Detection System) vs. IPS (Intrusion Prevention System)

IDS IPS
Detects intrusions but does not prevent them. Detects and prevents intrusions.
Monitoring system; requires human intervention. Control system; automatically blocks threats.

Key Elements of Cyber Security

  • Information security
  • Network security
  • Operational security
  • Application security
  • End-user education
  • Business continuity planning

Cryptography

Cryptography involves transforming data to protect it from unauthorized access. It uses mathematical techniques to encrypt (encode) data and decrypt (decode) it securely.

Threat, Vulnerability, and Risk

Threat Vulnerability Risk
Any potential danger that could exploit a vulnerability. A weakness that could be exploited by a threat. The likelihood of a threat exploiting a vulnerability.

Risk calculation: Risk = Likelihood of Threat * Impact of Vulnerability

Symmetric vs. Asymmetric Encryption

Symmetric Encryption Asymmetric Encryption
Uses the same key for encryption and decryption; faster but key exchange is a challenge. Uses separate keys for encryption and decryption (public and private keys); slower but safer key exchange.

CIA Triad (Reiterated)

The CIA triad (Confidentiality, Integrity, Availability) is a fundamental model in information security. It outlines the key principles for protecting information assets.

Encryption vs. Hashing

Encryption Hashing
Reversible; encrypted data can be decrypted. Irreversible; one-way function producing a fixed-size hash.
Used for protecting data confidentiality. Used for data integrity verification.
Two-way process (encryption and decryption); protects confidentiality. One-way process; protects data integrity. Cannot be reversed.

IDS (Intrusion Detection System) vs. IPS (Intrusion Prevention System)

IDS IPS
Detects malicious activity; alerts administrators. Detects and prevents malicious activity.
Passive; monitors network traffic. Active; can block or filter traffic.

Common Hashing Algorithms

  • MD5 (Message Digest Algorithm 5): Produces a 128-bit hash; vulnerable to collisions.
  • SHA (Secure Hash Algorithm): A family of cryptographic hash functions (SHA-1, SHA-256, SHA-512, etc.); more secure than MD5.
  • Tiger: A fast hashing algorithm producing a 192-bit hash.
  • RIPEMD: A family of hash functions.
  • Whirlpool: Produces a 512-bit hash.

Purpose of Hashing

Hashing is used for various purposes:

  • Data integrity checks (ensuring data hasn't been tampered with).
  • Password storage (storing password hashes instead of plain text).
  • Digital signatures.
  • Data deduplication.

Firewalls

A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. Firewalls help protect networks from unauthorized access and malicious activities.

Vulnerability Assessment (VA) vs. Penetration Testing (PT)

Vulnerability Assessment (VA) Penetration Testing (PT)
Identifies potential vulnerabilities in a system. Typically uses automated tools to scan for known vulnerabilities. Attempts to exploit vulnerabilities to assess the system's security. Often involves manual techniques and simulates real-world attacks.

Types of Hackers

  • Black Hat Hackers: Perform malicious hacking activities (illegal).
  • White Hat Hackers (Ethical Hackers): Perform security testing and assessments (legal and ethical).
  • Grey Hat Hackers: A blend of black and white hat techniques; may operate without explicit permission.

Traceroute

Traceroute is a network diagnostic tool that traces the path a packet takes to reach a destination. It helps identify network issues and routing problems.

VPNs (Virtual Private Networks)

VPNs create a secure, encrypted connection over a public network (like the internet). This protects data confidentiality and privacy.

Brute Force Attacks and Prevention

A brute-force attack attempts to guess passwords by trying many different combinations. Prevention involves techniques like:

  • Strong password policies (length, complexity).
  • Limiting login attempts.
  • Multi-factor authentication (MFA).

Port Scanning

Port scanning identifies open ports and services on a host. It's used by both administrators (for security audits) and attackers (to find vulnerabilities).

HIDS (Host-Based Intrusion Detection System) vs. NIDS (Network-Based Intrusion Detection System)

HIDS NIDS
Monitors individual hosts for malicious activity. Monitors network traffic for malicious activity.

Types of Cybersecurity

Cybersecurity encompasses various areas:

  • Network Security: Protecting networks and devices from threats.
  • Application Security: Securing software applications from vulnerabilities.
  • Identity and Access Management (IAM): Controlling user access to systems and data.
  • Data Security: Protecting data confidentiality, integrity, and availability.

Data Security, Operational Security, and Other Types of Security

Cybersecurity is multifaceted, encompassing various areas.

  • Data Security: Protecting data confidentiality and integrity during storage and transmission.
  • Operational Security: Managing and securing data assets (e.g., database encryption).
  • Mobile Security: Protecting data on mobile devices.
  • Cloud Security: Protecting data stored in cloud environments.

Unicasting, Multicasting, and Broadcasting

Unicasting Multicasting Broadcasting
One sender, one receiver. One or more senders, multiple receivers (a specific group). One sender, all receivers on the network.

Setting up a Firewall

  1. Change default passwords.
  2. Disable remote administration (unless absolutely necessary).
  3. Configure port forwarding for required applications.
  4. Disable the firewall's DHCP server if another DHCP server exists on the network.
  5. Enable logging to monitor activity.
  6. Implement and enforce robust security policies.

Patch Management in Cybersecurity

Patch management involves regularly updating software and systems to address known vulnerabilities. Patches should be applied promptly upon release to mitigate security risks.

Patch Management Tools

Patch management tools automate the process of identifying, downloading, and installing software updates:

  • Atera
  • NinjaRMM
  • Acronis Cyber Protect Cloud
  • PDQ Deploy
  • ManageEngine Patch Manager Plus
  • Microsoft System Center
  • Automox
  • SmartDeploy
  • SolarWinds Patch Manager

SSL (Secure Sockets Layer)

SSL (now largely replaced by TLS - Transport Layer Security) is a protocol that provides encrypted communication between a web server and a web browser, protecting data transmitted during online sessions.

Botnets

A botnet is a network of compromised computers (bots) controlled remotely by an attacker (bot herder). Botnets are often used for malicious purposes like sending spam, launching DDoS attacks, or stealing data.

Data Leakage

Data leakage is the unauthorized transfer of sensitive information outside a secure network.

Honeypots

Honeypots are decoy systems designed to attract and trap attackers, allowing security professionals to analyze attack methods and gather intelligence.

Shoulder Surfing

Shoulder surfing is a type of social engineering attack where an attacker looks over someone's shoulder to steal sensitive information (like passwords).

Common Cyber Security Attacks

  • Malware (viruses, worms, ransomware)
  • Phishing
  • Cross-Site Scripting (XSS)
  • Denial-of-Service (DoS) and Distributed Denial-of-Service (DDoS)
  • SQL Injection
  • Man-in-the-Middle (MITM) Attacks
  • Session Hijacking
  • Brute Force Attacks

Man-in-the-Middle (MITM) Attack

In a MITM attack, an attacker secretly intercepts communication between two parties, potentially modifying or stealing data.

Cross-Site Scripting (XSS) Attacks and Prevention

XSS attacks involve injecting malicious scripts into websites. Prevention techniques include input validation, output encoding, and using web application firewalls.

Stored XSS vs. Reflected XSS

Stored XSS Reflected XSS
Malicious script is permanently stored on the server. Malicious script is reflected back to the user from the server in the response.