Learning objectives

• Explain OWASP Top 10 the way a junior AppSec engineer would
• Map the idea to login, checkout, or API flows you already use
• Know a safe lab way to observe the issue (Juice Shop / CYNARKS Labs)
• Pass the knowledge check without attacking real sites

1. In one sentence

OWASP Top 10 is a priority map of common web risks — a shared language for developers and testers.

2. Why it matters (daily life)

Interviews, bug bounty triage, and AppSec roadmaps all reference it. It is categories, not a full checklist of every bug.

3. How it works

Current release is Top 10:2025 (A01 Broken Access Control … A10 Mishandling of Exceptional Conditions). Injection is A05:2025; SSRF sits under access control; supply chain is A03:2025. Keep 2021 codes only as historical. Map each lab finding to a 2025 category + fix. Full KB: /vulns.

4. Real-world / authorized lab example

Broken Access Control (A01:2025) often ranks high — IDOR on invoices fits here.

5. Fix mindset (builders)

Prefer input validation, parameterized queries / safe APIs, least-privilege sessions, security headers, and regression tests. “Patch later” is how IDOR and XSS become incidents.

6. Common mistakes

Memorizing 2021 numbers as if current; thinking Top 10 = only 10 bugs exist.

7. Practical habit (authorized labs only)

1. Reproduce on an intentional vulnerable app in Labs.
2. Capture request/response notes (redact secrets).
3. Write the fix in one paragraph a developer can ship.
4. Retest after the fix — same steps, expect fail-closed.

8. Memory tip

Explain this using Gmail login, Instagram, PhonePe checkout, or a college portal — as a story, without attacking real sites.

Practice intercepts only on authorized lab apps (e.g. Juice Shop in Labs).

Knowledge Check

Q1. Is Top 10 every bug?

A. Test only on authorized lab apps and report clear remediations
B. Probe live banking / college sites without written permission
C. Ignore HTTPS and mishandle sessions on purpose in production
D. Disable logging so findings cannot be traced

Q2. Name two 2025 categories.?

A. Test only on authorized lab apps and report clear remediations
B. Probe live banking / college sites without written permission
C. Ignore HTTPS and mishandle sessions on purpose in production
D. Disable logging so findings cannot be traced

Q3. Why do teams use it?

A. Test only on authorized lab apps and report clear remediations
B. Probe live banking / college sites without written permission
C. Ignore HTTPS and mishandle sessions on purpose in production
D. Disable logging so findings cannot be traced

Answer Key

1. A
2. A
3. A

Lesson Summary

OWASP Top 10 is a building block of modern web risk. Learn it deeply; practice only where you are allowed.

Coming next

Continue the Web Application Security syllabus. Keep your proxy pointed at lab targets only.

CYNARKS Academy – Learn to Understand. Practice to Defend.
Never test live PhonePe, Instagram, Razorpay merchant panels, or college portals without written permission.