OWASP Top 10: The 10 Commandments of Web Security

The OWASP (Open Web Application Security Project) is a worldwide community of security experts. Every few years, they publish the "Top 10": A list of the most dangerous security holes lurking in the web. For developers, this list is mandatory reading. Whoever controls these 10 points wards off 90% of all attacks. Here are the (updated) top candidates for 2026.

Featured Snippet: The OWASP Top 10 is the de facto standard for web application security. The current peak (Status 2025/26) is dominated by: 1. Broken Access Control (Users see data of others), 2. Cryptographic Failures (Bad encryption), and 3. Injection (SQL/Command Injection). Newer categories like Insecure Design emphasize that security must begin in the architecture.

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1. Broken Access Control (The Leader)

The Problem: A user can see data or execute actions they are not allowed to.

• Example: User A logs in and sees /account/123. He changes the URL to /account/124 and sees Data of User B.
• Or: A normal user calls /admin/deleteUser and it works because the server only checks "Is he logged in?", but not "Is he Admin?".

The Fix: Never trust the URL ID. Check in the backend at every access: if (currentUser.id != requestedResource.ownerId) throw Error("Forbidden"). Use central Middleware for Permissions.

2. Cryptographic Failures (Sensitive Data Leaks)

The Problem: Passwords in plaintext. Outdated encryption (MD5). HTTP instead of HTTPS. Or: Missing encryption in backups.

The Fix:

• HTTPS Everywhere.
• Argon2/bcrypt for passwords.
• AES-256 for databases.
• No sensitive data in URLs (GET parameters are logged!).

3. Injection (The Classic)

The Problem: The attacker smuggles code that the server executes.

• SQL Injection: ' OR 1=1 --
• Command Injection: ; rm -rf /

The Fix: Use Prepared Statements (Parameter Binding) in the database. Never concatenate strings ("SELECT * FROM users WHERE name = " + input). Use ORMs (Prisma, TypeORM) that do this automatically.

4. Insecure Design (Design Flaws)

The Problem: The software works technically perfectly, but the concept is insecure.

• Example: "Forgot Password" function says: "Email not found". -> Hacker now knows who is a customer (User Enumeration).

The Fix: Threat Modeling in the planning phase. Keep error messages generic ("If the email exists, we sent a link").

5. Security Misconfiguration

The Problem: Systems are installed insecurely.

• Default passwords (admin/admin).
• Debugging is on (Stack Trace shown in browser -> reveals server paths).
• S3 Buckets are public.

The Fix: Automated Hardening Scripts (Infrastructure as Code). No manual server configs.

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Myth-Busting: "XSS (Cross Site Scripting) is Dead"

Not dead, but slightly relegated (merged into "Injection"). Modern frameworks like React or Angular protect against XSS by default (they escape output automatically). But caution: Whoever uses dangerouslySetInnerHTML (React) or v-html (Vue) opens the gap again. Use Content Security Policy (CSP) headers as a second line of defence.

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Unasked Question: "What is SSRF (Server Side Request Forgery)?"

A climber in the charts. The hacker makes your server call a URL.

• Attack: "Load my profile picture from http://169.254.169.254/latest/meta-data/".
• That is the internal IP of AWS Cloud Metadata. The hacker steals your AWS Keys this way. Protection: Validate all URLs that users enter. Do not allow calls to internal IPs (Localhost/Intranet).

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FAQ: OWASP Top 10

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Related Articles:

• Content Security Policy
• Web Application Firewall
• Authentication Best Practices