Top 10 Cyber Security Interview Questions for Software Engineering Interviews
1. How Do You Ensure Secure Coding Practices?
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In software engineering, secure coding is essential to avoid vulnerabilities like SQL injection, cross-site scripting (XSS), or buffer overflows. Employers may ask how you integrate security into your development process.
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Example Scenario: You’re developing a web application. How do you protect user data from SQL injection attacks?
Answer: Use prepared statements with parameterized queries to ensure that input data is treated as values rather than executable code. Validate and sanitize user inputs rigorously. Implement role-based access control (RBAC) to prevent unauthorized data access.
2. What Is the Principle of Least Privilege, and How Do You Apply It?
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The Principle of Least Privilege (PoLP) is fundamental in cybersecurity, ensuring that users or systems have only the minimum access necessary to perform their tasks.
Example Scenario: Your software has multiple modules handling sensitive financial data. How do you secure these modules using PoLP?
Answer: Assign users or processes the minimum permissions required to execute their tasks. For instance, a marketing user should not have access to financial reports. At the code level, segregate different modules and enforce fine-grained access control.
3. How Would You Prevent Cross-Site Scripting (XSS) in a Web Application?
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Cross-Site Scripting (XSS) is a common vulnerability where attackers inject malicious scripts into web pages viewed by other users.
Example Scenario: You’re developing a social media application where users can post comments. How do you prevent malicious scripts from being executed?
Answer: Implement strict input validation and output encoding. Escape characters in user input that could be interpreted as executable code, such as `<`, `>`, and `&`. Use security headers like `Content-Security-Policy` (CSP) to mitigate the impact of XSS.
4. Explain the Differences Between Symmetric and Asymmetric Encryption
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Understanding encryption mechanisms is key to securing communication and data in software systems.
Example Scenario: You’re designing a secure messaging platform. When would you use symmetric versus asymmetric encryption?
Answer: Symmetric encryption (e.g., AES) uses the same key for both encryption and decryption, making it fast but requiring a secure key-sharing mechanism. It’s best for encrypting large amounts of data. Asymmetric encryption (e.g., RSA) uses a public/private key pair and is ideal for securely exchanging keys over an insecure channel before using symmetric encryption for the main communication.
5. What Is a Man-in-the-Middle Attack, and How Do You Defend Against It?
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A Man-in-the-Middle (MitM) attack occurs when an attacker intercepts communication between two parties.
Example Scenario: Your team is developing an e-commerce website. How do you prevent attackers from intercepting payment transactions?
Answer: Use Transport Layer Security (TLS) to encrypt data transmitted between the client and server, ensuring confidentiality and integrity. Implement strong mutual authentication using SSL certificates to confirm the identity of the server and, optionally, the client.
6. How Do You Handle Authentication and Authorization in a Distributed System?
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In distributed systems, managing user access securely is crucial.
Example Scenario: You’re building a microservices-based application where users interact with multiple services. How do you securely manage user authentication and authorization?
Answer: Implement centralized authentication with OAuth 2.0 or OpenID Connect, where a trusted identity provider (IdP) handles authentication. For authorization, use JSON Web Tokens (JWT) to securely pass user credentials between services, ensuring that each service validates the token before granting access.
7. How Do You Secure an API?
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APIs are vulnerable to attacks such as API key leaks or excessive data exposure.
Example Scenario: You’re building an API for a mobile application. How do you secure it?
Answer: Use HTTPS to encrypt API communication and prevent data interception. Implement authentication mechanisms like OAuth 2.0 or API keys, and enforce rate limiting to protect against abuse. Validate all input data and sanitize responses to prevent data leakage.
8. What Steps Would You Take to Prevent a Distributed Denial of Service (DDoS) Attack?
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DDoS attacks aim to overwhelm a service with traffic, rendering it unavailable.
Example Scenario: Your web application has recently experienced a spike in traffic, suspecting a DDoS attack. What measures do you implement?
Answer: Use a Content Delivery Network (CDN) and load balancers to distribute traffic and absorb malicious requests. Implement rate-limiting and IP blacklisting to block requests from suspicious sources. Additionally, services like AWS Shield or Cloudflare DDoS protection can help mitigate the attack.
9. How Do You Ensure Data Integrity During Data Transmission?
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Data integrity ensures that data hasn’t been tampered with during transmission.
Example Scenario: You’re developing a payment gateway that sends financial transaction data between systems. How do you ensure data integrity?
Answer: Use hashing algorithms such as SHA-256 to generate a hash of the data before transmission. The receiver recalculates the hash and compares it to the sent hash to ensure the data hasn’t been altered. Also, using TLS ensures data integrity and confidentiality in transit.
10. What Is Multi-Factor Authentication (MFA) and When Should It Be Used?
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MFA requires users to provide two or more verification factors to gain access to a system.
Example Scenario: You’re tasked with securing a sensitive internal tool used by employees. How do you implement multi-factor authentication?
Answer: Implement MFA by requiring something the user knows (password), something they have (a mobile app like Google Authenticator), or something they are (biometrics). This ensures that even if a password is compromised, the attacker cannot gain access without the second factor.
