How to Start Learning Web Security in 2025

Web security is one of the best career paths you can choose in 2025. The demand for security professionals continues to outpace supply, salaries are excellent, and the work is genuinely interesting—you're essentially learning to think like an attacker to defend systems.

But where do you start? The field can seem overwhelming with its alphabet soup of vulnerabilities (XSS, CSRF, SSRF, SQLi, IDOR...) and endless tools. This guide gives you a clear path from complete beginner to finding your first vulnerability.

Why Learn Web Security?

The Numbers

• $128,000 median salary for security engineers in the US (2024)
• 3.5 million unfilled cybersecurity jobs globally
• $500K+ paid out by major bug bounty programs annually
• 25% projected job growth through 2031 (much faster than average)

The Work

Unlike many tech jobs, security work is:

• Never boring - Every application is different, every bug is a puzzle
• High impact - You protect real users from real threats
• Continuously evolving - New technologies mean new vulnerabilities
• Flexible - Remote work, freelance/consulting, bug bounties

The Learning Path

Here's the order that makes sense. Each step builds on the previous:

Stage 1: Web Fundamentals (2-4 weeks)

You can't hack what you don't understand. Start with how the web actually works:

Learn:

• HTTP/HTTPS protocol (requests, responses, methods, headers)
• HTML structure and how browsers render pages
• JavaScript basics (DOM manipulation, events, fetch API)
• How cookies and sessions work
• Same-origin policy and CORS

Resources:

• MDN Web Docs - The definitive resource
• web.dev - Google's modern web guide
• Build something simple (a to-do app, blog) to solidify understanding

You're ready for Stage 2 when:

• You can explain what happens when you type a URL in your browser
• You understand the difference between GET and POST
• You know what cookies are and why they exist

Stage 2: Developer Tools (1-2 weeks)

Your browser's DevTools are your most important security tool:

Learn:

• Network tab - Inspect every request/response
• Console - Run JavaScript, see errors
• Elements - Modify the DOM in real-time
• Application - View cookies, localStorage, session storage
• Sources - Debug JavaScript, set breakpoints

Exercises:

1. Inspect the login request when you sign into any website
2. Find all cookies set by a site and understand each one
3. Modify form values before submission using DevTools
4. Find API endpoints by watching network traffic

Stage 3: Your First Vulnerabilities (4-6 weeks)

Start with the most common, most impactful vulnerabilities:

Week 1-2: Cross-Site Scripting (XSS)

XSS lets attackers inject JavaScript into pages other users visit.

<!-- Simple reflected XSS -->
Search results for: <script>alert('XSS')</script>

<!-- Stored XSS in a comment -->
Great article! <img src=x onerror=alert('XSS')>

Learn:

• Reflected vs. Stored vs. DOM-based XSS
• Common injection points (search, comments, profiles)
• Basic payloads and how to test
• Why XSS is dangerous (cookie theft, keylogging, defacement)

Week 3-4: SQL Injection

SQLi lets attackers manipulate database queries.

-- Login bypass
' OR '1'='1
-- Data extraction
' UNION SELECT username, password FROM users--

Learn:

• How SQL queries are built (and how they break)
• Error-based, union-based, and blind SQLi
• Common vulnerable patterns
• Why parameterized queries prevent SQLi

Week 5-6: Authentication Flaws

Broken authentication is consistently in the OWASP Top 10.

Learn:

• Weak password policies
• Credential stuffing and brute force
• Session management issues
• Password reset flaws

Stage 4: Expand Your Knowledge (Ongoing)

Once you're comfortable with the basics, expand to:

Access Control:

• IDOR (Insecure Direct Object Reference)
• Privilege escalation
• Missing function-level access control

Server-Side Vulnerabilities:

• SSRF (Server-Side Request Forgery)
• Path traversal
• Command injection

Client-Side Attacks:

• CSRF (Cross-Site Request Forgery)
• Clickjacking
• Open redirects

Modern Vulnerabilities:

• JWT attacks
• GraphQL vulnerabilities
• API security issues
• AI/LLM prompt injection

Free Learning Resources

Interactive Platforms

Reading

• OWASP Top 10 - The essential vulnerability list
• HackerOne Hacktivity - Real bug reports
• PortSwigger Research - Advanced techniques

YouTube Channels

• LiveOverflow - Deep dives into vulnerabilities
• John Hammond - CTF walkthroughs
• IppSec - Hack The Box walkthroughs
• STÖK - Bug bounty hunting

Tools You'll Need

Essential (Free)

Browser DevTools    - Already installed
Burp Suite Community - Web proxy (intercept/modify traffic)
curl                - Command-line HTTP requests
Postman             - API testing

Useful Later

sqlmap      - Automated SQL injection
ffuf        - Web fuzzer
Nuclei      - Vulnerability scanner
Nmap        - Network scanning

Don't Buy Yet

Resist the urge to buy expensive tools or courses early on. Free resources are more than enough to get started. Invest money only after you've exhausted free options and know exactly what you need.

Practice Environment

Legal Practice Targets

Never test on systems without permission. Use these instead:

Intentionally Vulnerable Apps:

• DVWA - Damn Vulnerable Web Application
• bWAPP - Buggy Web Application
• Juice Shop - Modern vulnerable app
• WebGoat - OWASP's learning platform

Bug Bounty Programs:

• Start with programs that explicitly welcome beginners
• Look for programs with large scopes and responsive teams
• HackerOne and Bugcrowd list program difficulty levels

Our Platform: Practice web security vulnerabilities with guided challenges at AliceSec challenges. Each vulnerability type has multiple levels from beginner to advanced.

Common Beginner Mistakes

1. Skipping Fundamentals

Mistake: Jumping straight to tools and exploits without understanding how web apps work.

Fix: Spend time in Stage 1. Build a simple web app. You'll understand vulnerabilities much better.

2. Tool Dependency

Mistake: Running automated scanners without understanding what they do.

Fix: Learn to find vulnerabilities manually first. Tools are supplements, not substitutes for knowledge.

3. Chasing Complexity

Mistake: Trying to learn advanced attacks before mastering basics.

Fix: Get really good at XSS and SQLi before moving on. These fundamentals appear everywhere.

4. Not Taking Notes

Mistake: Practicing without documenting what you learn.

Fix: Keep a security journal. Document every vulnerability you find, how you found it, and how it was fixed.

5. Giving Up Too Early

Mistake: Expecting to find bugs immediately.

Fix: Everyone struggles at first. The first vulnerability is the hardest. Keep practicing.

Your First 30 Days

Here's a concrete plan:

Week 1: Foundations

• Day 1-3: HTTP basics, browser DevTools
• Day 4-5: Build a simple web form (HTML/JS)
• Day 6-7: Set up Burp Suite, intercept your own traffic

Week 2: XSS Deep Dive

• Day 8-10: Learn XSS theory, try basic payloads
• Day 11-14: Complete XSS labs on PortSwigger or our XSS challenges

Week 3: SQL Injection

• Day 15-17: Learn SQL basics and injection theory
• Day 18-21: Complete SQLi labs, try sqlmap on intentionally vulnerable apps

Week 4: Authentication

• Day 22-24: Study authentication vulnerabilities
• Day 25-28: Practice on WebGoat or similar
• Day 29-30: Review, consolidate notes, plan next steps

What's Next?

After completing this path, you'll have the foundation to:

1. Continue learning - Move to advanced topics, specialize in an area
2. Start bug bounty hunting - Find real vulnerabilities for money
3. Pursue certifications - OSCP, CEH, Security+
4. Apply for security jobs - Junior penetration tester, security analyst
5. Build security tools - Contribute to open source security projects

Getting Help

The security community is generally welcoming to beginners:

• Discord servers - Many learning platforms have active communities
• Reddit - r/netsec, r/AskNetsec, r/bugbounty
• Twitter/X - Follow security researchers, engage with their content
• Local meetups - OWASP chapters, DEF CON groups, security BSides

Don't be afraid to ask questions. Everyone was a beginner once.

Start Now

The best time to start learning web security was yesterday. The second best time is now.

Pick one resource from this guide and begin. Don't overthink it—just start. You'll figure out your specific interests and path as you learn.

Try our beginner XSS challenges to get your hands dirty right now.

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This guide will be updated as the field evolves. Last updated: December 2025.