Node.js is a powerful platform that drives many modern web applications. But like any technology, it’s not immune to security threats. If not properly secured, Node.js applications can be vulnerable to a wide range of attacks — from brute force attempts to database breaches. This article explores the most common security risks in Node.js and offers practical tips to protect your application.

1. 🔐 Compromised Databases

What is it?
A compromised database occurs when an attacker breaks into your database and steals sensitive data such as user information, passwords, or credit card details.

How does it happen?

• Exposed or weak database credentials

• Unencrypted database connections

• Poor access controls

• Lack of network-level protection

How to prevent it:

• Store credentials in environment variables (.env) and never commit them to version control.

• Use encrypted database connections (SSL/TLS).

• Limit user permissions based on the principle of least privilege.

• Implement IP whitelisting or VPN access for your database.

• Hash sensitive data like passwords using bcrypt.

2. 🧠 Brute Force Attacks

What is it?
Brute force attacks are performed by repeatedly guessing usernames and passwords to gain access to a system.

How does it happen?

• No rate limiting on login attempts

• Weak or predictable passwords

• No CAPTCHA mechanism

How to prevent it:

• Use rate-limiting middleware like express-rate-limit.

• Add CAPTCHA to forms (e.g., Google reCAPTCHA).

• Implement maximum login attempts.

• Use bcrypt to make login requests slow.

3. ✴️ Cross-site Scripting (XSS)

What is it?
XSS allows attackers to inject malicious scripts into web pages, which then run in other users’ browsers. This can lead to session hijacking, data theft, or redirection to malicious sites.

How does it happen?

• Unsanitized user input rendered in HTML pages

• Lack of content security policies

How to prevent it:

• Sanitize user input using libraries like xss or sanitize-html.

• Store JWT in HTTPOnly cookies.

• Use security headers with helmet.

• Implement a Content Security Policy (CSP).

4. 🌐 Denial-of-Service (DoS) Attacks

What is it?
A DoS attack floods your server with requests, overloading it until it crashes or becomes unresponsive.

How does it happen?

• No rate limiting

• Large payloads in requests

• Expensive operations (e.g., infinite loops)

How to prevent it:

• Implement rate limiting(express-rate-limit).

• Set payload size limits (body-parser with limit option).

• Avoid bad regular expressions.

5. 🧾 NoSQL Injection

What is it?
NoSQL injection takes place when malicious queries are injected into a NoSQL database like MongoDB through manipulating request inputs.

How does it happen?
If you do not sanitize inputs, a user might send:

{ "username": { "$gt": "" } }

in order to skip authentication.

How to prevent it:

• Use ORM's like mongoose (for mongoDB).

• Sanitize user input.

7. ⚠️ Insecure Cookies and JWT Misuse

What is it?
Improper handling of cookies or JWT tokens can lead to session hijacking and unauthorized access.

How to prevent it:

• Use httpOnly, secure, and sameSite=strict for cookies.

• Keep JWT secrets secure and rotate them periodically.

• Make JWTs short-lived and use refresh tokens for session continuity.

• Store sensitive tokens securely on the client (preferably not in localStorage).

Security in Node.js isn’t just about avoiding bugs — it’s about protecting users, data, and your application’s integrity. The risks are real, but with a proactive approach and the right tooling, most threats can be mitigated. Keep your dependencies updated, validate and sanitize everything, and never stop auditing your app for vulnerabilities.
Security isn’t a one-time task — it’s a continuous responsibility.