Node.Js Security Interview Questions

Checkout Vskills Interview questions with answers in Node.js Security to prepare for your next job role. The questions are submitted by professionals to help you to prepare for the Interview.

Q.1 What is Node.js?

Node.js is a runtime environment that allows you to run JavaScript on the server, enabling server-side scripting and applications.

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Q.2 Why is security important in Node.js applications?

Security is crucial to protect Node.js applications from vulnerabilities and attacks, ensuring data integrity and user trust.

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Q.3 What is Cross-Site Scripting (XSS)?

XSS is a security vulnerability where an attacker injects malicious scripts into a web application, which are then executed by users' browsers.

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Q.4 How can you prevent XSS attacks in Node.js?

Prevent XSS by properly validating and sanitizing user inputs, using templating engines that escape data, and setting HTTP headers like Content Security Policy (CSP).

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Q.5 What is Cross-Site Request Forgery (CSRF)?

CSRF is an attack where an attacker tricks a user into performing actions on a website without their knowledge or consent when they are authenticated.

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Q.6 How can you prevent CSRF attacks in Node.js?

Prevent CSRF by using anti-CSRF tokens, checking the referrer header, and ensuring that sensitive actions require authentication and authorization.

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Q.7 What is SQL Injection, and how can it be mitigated in Node.js?

SQL Injection is an attack where an attacker inserts malicious SQL queries into input fields. Prevent it by using parameterized queries and input validation.

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Q.8 What is the principle of the "least privilege" in security?

The principle of least privilege means giving users or processes the minimum access rights or permissions necessary to perform their tasks, reducing potential risks.

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Q.9 How can you secure sensitive data in Node.js applications?

Secure sensitive data by encrypting it using strong algorithms, storing it in environment variables, and following encryption best practices.

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Q.10 What is a security audit, and why is it important for Node.js apps?

A security audit is a thorough review of an application's code and architecture to identify vulnerabilities. It's important to ensure the app's security posture.

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Q.11 What is a DoS (Denial of Service) attack?

A DoS attack aims to make a service or application unavailable to users by overwhelming it with excessive traffic, requests, or resource consumption.

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Q.12 How can you mitigate DoS attacks in Node.js?

Mitigate DoS attacks by implementing rate limiting, using load balancers, and monitoring for unusual traffic patterns or resource usage.

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Q.13 What is a DDoS (Distributed Denial of Service) attack?

A DDoS attack involves multiple compromised devices attacking a target simultaneously, making it difficult to mitigate.

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Q.14 How can you protect against DDoS attacks in Node.js?

Protection against DDoS attacks often involves using specialized services, firewalls, and traffic filtering techniques provided by cloud providers.

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Q.15 What is a security token, and how is it used in Node.js?

A security token is a piece of data used to authenticate and authorize users. In Node.js, tokens are often used for authentication and session management.

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Q.16 What is JWT (JSON Web Token), and how does it work in Node.js?

JWT is a compact, URL-safe means of representing claims to be transferred between two parties. In Node.js, it is often used for authentication and authorization.

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Q.17 How do you protect JWTs from tampering in Node.js?

Protect JWTs by signing them with a secret key, validating their signatures, and setting expiration times to limit their validity.

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Q.18 What is OWASP, and why is it important for Node.js security?

OWASP (Open Web Application Security Project) is an organization that provides resources and guidelines for web application security, making it important for Node.js developers to follow best practices.

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Q.19 What is CORS (Cross-Origin Resource Sharing)?

CORS is a security feature that controls which domains are allowed to access resources on a web page, preventing unauthorized cross-origin requests.

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Q.20 How can you configure CORS in Node.js applications?

Configure CORS in Node.js by using middleware like "cors" to define allowed origins, headers, and HTTP methods for cross-origin requests.

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Q.21 What are security headers, and how can they enhance Node.js security?

Security headers are HTTP headers that provide security-related instructions to the browser. Examples include Content Security Policy (CSP) and X-Content-Type-Options. They enhance Node.js security by preventing certain types of attacks.

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Q.22 What is a Content Security Policy (CSP) in Node.js?

CSP is a security feature that controls which resources can be loaded and executed by a web page, protecting against XSS attacks.

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Q.23 How do you implement a Content Security Policy (CSP) in Node.js?

You implement CSP by setting the "Content-Security-Policy" HTTP header and specifying allowed sources for scripts, styles, and other resources.

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Q.24 What is the role of authentication in Node.js security?

Authentication verifies the identity of users or systems, ensuring that only authorized individuals or processes can access protected resources.

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Q.25 How can you implement user authentication in Node.js?

Implement user authentication in Node.js using libraries like Passport.js or by building custom authentication middleware with features like sessions and tokens.

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Q.26 What is the difference between authentication and authorization?

Authentication verifies identity, while authorization determines what actions and resources a user is allowed to access based on their identity.

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Q.27 How can you prevent brute-force attacks on user accounts in Node.js?

Prevent brute-force attacks by implementing account lockout mechanisms, rate limiting login attempts, and using CAPTCHA challenges.

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Q.28 What is a session management in Node.js, and why is it important?

Session management involves tracking user sessions, which is crucial for maintaining user state, implementing security measures, and ensuring a secure user experience.

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Q.29 How can you implement session management in Node.js?

Implement session management using libraries like "express-session" and store session data securely, often in databases or in-memory stores.

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Q.30 What is "bcrypt," and how is it used for password hashing in Node.js?

Bcrypt is a cryptographic hash function used to securely hash passwords. In Node.js, it is commonly used for hashing and verifying user passwords.

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Q.31 What is the role of the "Helmet" middleware in Node.js?

Helmet is a middleware package that helps secure Express.js applications by setting various HTTP headers, such as CSP and HSTS, to mitigate common web vulnerabilities.

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Q.32 How can you securely manage environment variables in Node.js?

Store sensitive data like API keys and database credentials in environment variables and use packages like "dotenv" to manage them securely.

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Q.33 What is the "secure" flag for cookies, and why is it important in Node.js security?

The "secure" flag in cookies restricts them to secure (HTTPS) connections, preventing sensitive information from being sent over unencrypted connections.

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Q.34 How can you enforce the "secure" flag for cookies in Node.js?

Set the "secure" flag for cookies in Node.js by configuring your server to use HTTPS, ensuring that cookies are transmitted securely.

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Q.35 What is HTTP Public Key Pinning (HPKP), and how does it enhance Node.js security?

HPKP is a security feature that helps protect against certificate impersonation attacks by associating public keys with a specific domain. It enhances Node.js security by preventing rogue certificates.

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Q.36 How do you implement HTTP Public Key Pinning (HPKP) in Node.js?

Implement HPKP by configuring the "Public-Key-Pins" HTTP header to specify which public keys should be trusted for a specific domain.

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Q.37 What is "sandboxing" in the context of Node.js security?

Sandboxing is a technique that restricts the execution environment of code, reducing potential security risks by limiting access to resources and system APIs.

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Q.38 How can you implement code sandboxing in Node.js applications?

Implement code sandboxing by using libraries or techniques that isolate untrusted code, such as Docker containers or virtualization.

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Q.39 What are the security implications of third-party modules in Node.js?

Third-party modules can introduce security vulnerabilities if not carefully reviewed and maintained. Developers should regularly update and audit dependencies.

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Q.40 How can you automate the detection of security vulnerabilities in Node.js dependencies?

Use tools like npm audit, npm audit fix, and third-party services like Snyk to automate vulnerability detection and resolution in Node.js dependencies.

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Q.41 What is the "Same-Origin Policy" (SOP) in web security?

SOP is a security feature that restricts web pages from making requests to a different domain, protecting against unauthorized cross-origin requests.

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Q.42 How can you enhance the Same-Origin Policy (SOP) in Node.js?

You can enhance SOP by configuring CORS (Cross-Origin Resource Sharing) headers and implementing security headers like Content Security Policy (CSP).

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Q.43 What is the purpose of the "crypto" module in Node.js?

The "crypto" module provides cryptographic functionality, including encryption, decryption, hashing, and digital signatures, enhancing security in Node.js applications.

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Q.44 How do you securely generate random numbers in Node.js?

Use the "crypto" module's "randomBytes" method to generate cryptographically secure random numbers in Node.js.

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Q.45 What is HTTPS, and why is it important for Node.js security?

HTTPS is a secure communication protocol that encrypts data transmitted between a client and a server, protecting against eavesdropping and data tampering. It is essential for securing Node.js applications.

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Q.46 How do you set up HTTPS for a Node.js application?

Set up HTTPS for a Node.js application by obtaining an SSL/TLS certificate, configuring the server to use the certificate, and listening on the HTTPS port.

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Q.47 What is a "man-in-the-middle" (MITM) attack, and how can it be prevented in Node.js?

A MITM attack intercepts communication between two parties. It can be prevented in Node.js by using HTTPS, ensuring the authenticity of certificates, and implementing security headers.

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Q.48 How can you protect against JavaScript injection attacks in Node.js?

Protect against JavaScript injection by validating and sanitizing user inputs, using parameterized queries for database access, and implementing proper encoding and escaping mechanisms.

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Q.49 What is the "npm audit" command in Node.js, and why is it useful for security?

npm audit is a command that checks Node.js dependencies for known security vulnerabilities. It's useful for identifying and addressing security issues in your project's dependencies.

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Q.50 What is a "security misconfiguration" vulnerability?

Security misconfigurations occur when a system or application is not properly configured, leaving it vulnerable to attacks.

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Q.51 How can you mitigate security misconfigurations in Node.js?

Mitigate security misconfigurations by following best practices, regularly reviewing configuration files, and using security tools like linters and scanners.

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Q.52 What are "environment variables," and how are they used for Node.js security?

Environment variables are variables external to the application that store sensitive information like API keys and secrets. They are used to keep sensitive data out of source code.

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Q.53 What is a "JSON Web Token" (JWT), and how is it used for authentication in Node.js?

A JWT is a compact, self-contained means of representing claims to be transferred between two parties. It is often used for authentication in Node.js applications.

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Q.54 How do you securely store passwords in Node.js databases?

Securely store passwords by using strong cryptographic hashing algorithms like bcrypt and salting before storing them in the database.

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Q.55 What is "data validation," and why is it important for Node.js security?

Data validation involves verifying that input data meets specific criteria. It is important for Node.js security to prevent injection attacks and other vulnerabilities.

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Q.56 How can you validate and sanitize user inputs in Node.js?

Validate and sanitize user inputs by using libraries like Joi or implementing custom validation functions to ensure data integrity and security.

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Q.57 What is the purpose of "JWT expiration" in Node.js authentication?

JWT expiration limits the validity period of a token, reducing the risk of unauthorized access if a token is compromised.

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Q.58 How can you handle user sessions securely in Node.js?

Handle user sessions securely by using secure cookies, session tokens, and protecting session data from tampering and hijacking.

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Q.59 What is the role of "secure HTTP headers" in Node.js security?

Secure HTTP headers provide instructions to the browser to enhance security, such as preventing content loading from untrusted sources and enforcing secure connections.

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Q.60 How can you prevent information disclosure in error messages in Node.js?

Prevent information disclosure by configuring error handling to display generic error messages to users while logging detailed error information for developers.

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Q.61 What is "Input Validation" in Node.js security?

Input validation involves ensuring that data provided by users or external sources meets the expected format and security requirements.

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Q.62 How can you protect against SQL injection in Node.js?

Protect against SQL injection by using parameterized queries and avoiding dynamic SQL queries constructed from user input.

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Q.63 What is the role of the "express-session" middleware in Node.js?

express-session is a middleware that helps manage user sessions in Express.js applications by storing session data and associating it with a session identifier.

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Q.64 How can you prevent insecure direct object references (IDOR) in Node.js?

Prevent IDOR by implementing proper authorization checks and ensuring that users can only access resources they are authorized to access.

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Q.65 What is the importance of keeping Node.js and its dependencies updated for security?

Keeping Node.js and dependencies updated is essential to patch known security vulnerabilities and maintain a secure application.

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Q.66 How do you handle password recovery and reset securely in Node.js?

Handle password recovery and reset securely by implementing multi-step verification processes, securely generating and sending reset tokens, and validating user identity.

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Q.67 What is "rate limiting," and why is it important for Node.js security?

Rate limiting restricts the number of requests a client can make to a server within a specified time frame, preventing abuse and DoS attacks.

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Q.68 How can you implement rate limiting in Node.js applications?

Implement rate limiting using middleware or dedicated libraries to control the number of requests per IP address, user, or API endpoint.

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Q.69 What is "security through obscurity," and why is it not recommended in Node.js?

Security through obscurity is the practice of relying on the secrecy of implementation details for security. It is not recommended because it is not a robust security strategy.

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Q.70 What are the common security headers used in Node.js applications?

Common security headers include Content Security Policy (CSP), Strict Transport Security (HSTS), X-Content-Type-Options, and X-Frame-Options.

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Q.71 What is a "sensitive data exposure" vulnerability?

Sensitive data exposure occurs when an application does not adequately protect sensitive information like passwords, credit card numbers, or personal data.

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Q.72 How can you prevent sensitive data exposure in Node.js applications?

Prevent data exposure by using encryption for data at rest and in transit, and following data protection regulations like GDPR and HIPAA where applicable.

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Q.73 What is the "npm outdated" command in Node.js, and why is it useful for security?

npm outdated checks for outdated packages in a Node.js project, helping developers identify and update dependencies with known security vulnerabilities.

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Q.74 What is a "security patch," and why should you apply them in Node.js?

A security patch is a software update that fixes a specific security vulnerability. It should be applied in Node.js to protect the application from known threats.

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Q.75 How can you implement role-based access control (RBAC) in Node.js applications?

Implement RBAC by associating roles with users and defining permissions for each role, then checking authorization based on the user's role and requested actions.

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Q.76 What is the "Etag" header, and how does it relate to caching in Node.js?

The "Etag" header is used to check if a resource has changed since it was last retrieved, helping to reduce bandwidth usage and improve caching efficiency.

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Q.77 How can you secure RESTful APIs in Node.js?

Secure RESTful APIs in Node.js by using authentication, authorization, rate limiting, input validation, and protection against common API vulnerabilities like SQL injection.

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Q.78 What is the "Node.js Security Working Group"?

The Node.js Security Working Group is a community effort to improve the security of Node.js and its ecosystem by identifying and addressing security vulnerabilities.

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Q.79 What is the "npm audit" report, and how can you interpret it?

The "npm audit" report provides information about security vulnerabilities in a Node.js project's dependencies, including the severity and recommended actions to resolve them.

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Q.80 How can you prevent unauthorized access to sensitive APIs in Node.js?

Prevent unauthorized access by implementing authentication mechanisms like API keys, OAuth, or JWT, and enforcing proper authorization checks.

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Q.81 What is "content sniffing," and why should you disable it in Node.js security?

Content sniffing is a browser feature that attempts to determine the type of content served by a web server. Disabling it can prevent certain security risks, such as MIME type confusion.

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Q.82 How can you prevent clickjacking attacks in Node.js?

Prevent clickjacking by setting the "X-Frame-Options" HTTP header to deny or restrict framing, preventing the rendering of your site in a frame.

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Q.83 What is the "npm audit fix" command in Node.js?

npm audit fix is a command that attempts to automatically resolve known security vulnerabilities in a Node.js project's dependencies by updating them to patched versions.

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Q.84 What is a "security incident response plan," and why is it important for Node.js applications?

A security incident response plan outlines procedures for detecting, responding to, and mitigating security incidents. It's important for handling security breaches effectively.

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Q.85 How can you ensure the secure storage of API keys in Node.js applications?

Store API keys securely by using environment variables, encrypted configuration files, or dedicated secrets management solutions like AWS Secrets Manager or HashiCorp Vault.

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Q.86 What is the "dotenv" module in Node.js, and how can it enhance security?

dotenv is a module for loading environment variables from a ".env" file. It enhances security by separating sensitive data from the codebase and preventing accidental exposure.

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Q.87 How can you prevent code injection attacks in Node.js?

Prevent code injection by using safe templating engines, input validation, and escaping user inputs before rendering them in HTML, JavaScript, or other contexts.

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Q.88 What is the "NoSQL injection" vulnerability, and how can you prevent it in Node.js?

NoSQL injection is a type of attack against NoSQL databases. Prevent it by using parameterized queries or using libraries that handle query construction securely.

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Q.89 What is the "Promise" object, and how is it used for asynchronous programming in Node.js?

Promises are objects representing the eventual completion or failure of an asynchronous operation. They are used to handle asynchronous tasks in a more structured way.

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Q.90 How can you prevent unauthorized file access in Node.js applications?

Prevent unauthorized file access by using proper file permissions, restricting access through middleware or routes, and implementing access control mechanisms.

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Q.91 What is "security education and training," and why is it essential for Node.js developers?

Security education and training help developers understand security best practices and threats, empowering them to make informed decisions and write secure code.

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Q.92 How do you handle and store user passwords securely in Node.js?

Handle user passwords securely by using strong hashing algorithms (e.g., bcrypt), salting, and applying security practices like password policies.

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Q.93 How can you enforce strong password policies in Node.js applications?

Enforce strong password policies by setting minimum requirements for password complexity (length, characters, etc.) and prompting users to choose strong passwords.

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Q.94 What is "two-factor authentication" (2FA), and why is it important in Node.js security?

2FA adds an additional layer of security by requiring users to provide two forms of verification (e.g., a password and a one-time code) to access their accounts. It's important for reducing the risk of unauthorized access.

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Q.95 How do you implement two-factor authentication (2FA) in Node.js applications?

Implement 2FA by integrating authentication libraries that support 2FA, such as TOTP or SMS-based verification, and enforcing 2FA for sensitive account operations.

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Q.96 What is "input encoding" in Node.js, and why is it important for security?

Input encoding involves specifying the character encoding of input data. It is important for security to prevent encoding-based attacks like UTF-8 homoglyph attacks.

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Q.97 How can you prevent encoding-based attacks in Node.js?

Prevent encoding-based attacks by enforcing consistent input encoding and rejecting input with invalid or suspicious encoding.

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Q.98 What are the security benefits of using prepared statements in Node.js database queries?

Prepared statements protect against SQL injection by separating SQL code from user input, ensuring that input is treated as data, not executable code.

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Q.99 What is "access control," and why is it important for Node.js security?

Access control determines who can access what resources and perform specific actions. It's important for protecting sensitive data and functionalities.

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Q.100 How can you implement access control in Node.js applications?

Implement access control by defining user roles and permissions, checking authorization before granting access, and enforcing least privilege principles.

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Q.101 What is "certificate pinning," and how does it enhance security in Node.js?

Certificate pinning is a security technique that associates a specific SSL/TLS certificate with a domain, preventing impersonation attacks. It enhances the security of encrypted communication.

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Q.102 How can you implement certificate pinning in Node.js applications?

Implement certificate pinning by validating that the server's certificate matches a known and trusted certificate fingerprint or public key.

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Q.103 What is the "public key infrastructure" (PKI), and how does it relate to Node.js security?

PKI is a framework that manages digital keys and certificates. It plays a role in securing communication, authentication, and encryption in Node.js applications.

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Q.104 How can you securely store and manage private keys in Node.js applications?

Securely store private keys by using hardware security modules (HSMs), dedicated key management solutions, or strong encryption with proper access controls.

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Q.105 What is the role of the "crypto" module in protecting sensitive data in Node.js applications?

The "crypto" module provides cryptographic functions for securing data at rest, encrypting communications, and generating secure random numbers.

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Q.106 How can you protect against "session fixation" attacks in Node.js?

Protect against session fixation by generating a new session ID after a successful login and ensuring that session IDs are not predictable or easy to guess.

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Q.107 What is the "npm audit" severity scale, and how can it help prioritize security fixes?

The "npm audit" severity scale categorizes vulnerabilities as "low," "moderate," "high," and "critical," helping developers prioritize and address the most severe security issues first.

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Q.108 How do you ensure the security of RESTful API endpoints in Node.js applications?

Ensure API security by using authentication, authorization, input validation, proper error handling, and protection against common API vulnerabilities like CSRF and SQL injection.

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Q.109 What is the "OWASP Top Ten" list, and why is it relevant to Node.js security?

The OWASP Top Ten is a list of the most critical web application security risks. It is relevant to Node.js security as it highlights common vulnerabilities to be aware of and mitigate.

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Q.110 How can you monitor and log security events in Node.js applications?

Implement logging and monitoring mechanisms to record security events, such as failed login attempts, access control violations, and unauthorized access, for analysis and alerting.

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