Understanding OWASP Top 10
Familiarize yourself with the most critical web application security risks and how they apply to Node.js.
Understanding OWASP Top 10 is a free Node.js Backend Development Bootcamp lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Node.js Backend Development Bootcamp learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
What is OWASP Top 10?
Welcome! Today we'll explore the OWASP Top 10, a crucial guide for web security.
OWASP stands for the Open Web Application Security Project. It's a non-profit foundation focused on improving software security.
The OWASP Top 10 is a standard awareness document for developers and security professionals. It lists the most critical web application security risks.

A03:2021 Injection
Injection is when untrusted data is sent to an interpreter as part of a command or query. This tricks the interpreter into executing unintended commands.
Think SQL, NoSQL, or Command Injection. In Node.js, if you build database queries or system commands using unsanitized user input, you're vulnerable.
An attacker could, for example, bypass login, alter data, or even execute system commands.
A07:2021 Auth. Failures
Identification and Authentication Failures (formerly Broken Authentication) occur when user identity, authentication, or session management is improperly implemented.
This can lead to attackers compromising passwords, session tokens, or exploiting weak authentication flows to assume other users' identities.
Common issues include weak password policies, unsecure session IDs, or improper credential storage in Node.js apps.
A01:2021 Broken Access Control
Broken Access Control means users can act outside their intended permissions. This is a very common vulnerability.
For example, a regular user might access administrator functions, or a user can view another user's private data by simply changing an ID in the URL.
In Node.js, this often happens when authorization checks are missing or incorrectly implemented in routes or middleware.
A02:2021 Cryptographic Failures
Cryptographic Failures (formerly Sensitive Data Exposure) happen when sensitive data is not properly protected, either at rest (stored) or in transit (sent over networks).
If data like passwords, financial details, or PII (Personally Identifiable Information) isn't encrypted, or weak encryption is used, it can be exposed.
Node.js applications must ensure proper use of HTTPS, strong encryption algorithms, and secure storage for sensitive data.
A05:2021 Security Misconfiguration
Security Misconfiguration is often a result of insecure default configurations, incomplete configurations, or leaving unnecessary features enabled.
Examples include:
- Default accounts with weak passwords
- Unpatched flaws in servers or frameworks
- Exposed cloud storage buckets
- Leaving error messages that reveal sensitive system info
Node.js developers must secure their environment, server settings, and dependencies.
A06:2021 Vulnerable Components
Vulnerable and Outdated Components refers to using libraries, frameworks, or other software modules with known security vulnerabilities.
Node.js projects heavily rely on npm packages. If these packages have known weaknesses and are not updated, your entire application becomes vulnerable.
Always keep your dependencies up-to-date and regularly scan for known vulnerabilities.
A08:2021 Data Integrity Failures
Software and Data Integrity Failures happen when code or data integrity is compromised, often due to relying on untrusted sources.
This includes insecure deserialization (reconstructing data from untrusted sources) or not verifying the integrity of software updates or critical data.
In Node.js, ensure any deserialized data is trusted and that package sources are secure.
A10:2021 SSRF
Server-Side Request Forgery (SSRF) occurs when a web application fetches a remote resource without validating the user-supplied URL.
An attacker can trick the application into sending requests to an unintended destination. This could be internal systems, other external services, or even the localhost.
In Node.js, if your server fetches content from URLs provided by users, careful validation is key to prevent SSRF.
Test Your Knowledge
Which of the following describes the OWASP Top 10 risk of Broken Access Control?
Recap: OWASP Top 10
Great job! We've covered the basics of the OWASP Top 10 and some of its most critical risks:
- Injection: Malicious input manipulating commands.
- Auth. Failures: Weak identity and session management.
- Broken Access Control: Unauthorized resource access.
- Cryptographic Failures: Poor data protection.
- Security Misconfiguration: Insecure defaults or settings.
- Vulnerable Components: Using outdated or compromised libraries.
- Data Integrity Failures: Compromised code or data trust.
- SSRF: Server making unintended requests.
Understanding these risks is the first step towards building secure Node.js applications!
Frequently asked questions
Is the “Understanding OWASP Top 10” lesson free?
Yes — the full text of “Understanding OWASP Top 10” is free to read here on the web, and the Node.js Backend Development Bootcamp course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Node.js Backend Development Bootcamp course, upgrade to CoddyKit PRO.
What will I learn in “Understanding OWASP Top 10”?
Familiarize yourself with the most critical web application security risks and how they apply to Node.js. You practise Node.js Backend Development Bootcamp with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Node.js Backend Development Bootcamp?
No prior experience is required. Node.js Backend Development Bootcamp on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Understanding OWASP Top 10” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Node.js Backend Development Bootcamp lesson?
Yes. Every Node.js Backend Development Bootcamp lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Understanding OWASP Top 10
- Secure Coding Practices in Node.js
- Data Encryption & Hashing
- Rate Limiting & Brute-Force Protection