94% of web applications contain at least one OWASP Top 10 vulnerability (Verizon 2023 DBIR). This tutorial covers exploitation techniques, real-world case studies, and professional remediation strategies for each critical risk.
OWASP Top 10: Web Application Security Masterclass
OWASP Vulnerability Prevalence (2023)
1. Injection Vulnerabilities
Types:
- SQLi: Database command injection
- OS Command: Shell command execution
- LDAP: Directory service manipulation
Exploitation:
# SQLi UNION attack ' UNION SELECT username, password FROM users-- # SQLmap automation sqlmap -u "http://test.com?id=1" --dbs # Command injection ; cat /etc/passwd
Enterprise Case:
2017 Equifax breach (CVE-2017-5638) exposed 143M records via SQLi
2. Broken Authentication
Attack Vectors:
- Credential Stuffing: Reused password databases
- Session Fixation: Cookie manipulation
- Weak 2FA: SMS/email bypass
Testing Methods:
- Burp Suite Intruder for brute force
- OWASP ZAP for session analysis
- Custom wordlists with Crunch
Remediation:
Implement passwordless auth (WebAuthn) and rate limiting
3. Sensitive Data Exposure
Common Failures:
- Clear-text Storage: Unencrypted databases
- Weak Algorithms: MD5, SHA1 hashing
- Improper Headers: Missing HSTS/CSP
Discovery Tools:
# TLS scan with testssl testssl.sh -E https://example.com # Search for exposed data gitleaks --repo-url=https://github.com/example/repo # Detect cache headers curl -I https://example.com | grep -i cache-control
GDPR Impact:
Fines up to 4% of global revenue for PII exposure
4. XML External Entities (XXE)
Exploitation Methods:
- File Disclosure: Extract /etc/passwd
- SSRF: Internal network scanning
- DoS: Billion laughs attack
Payload Examples:
]>&xxe; ]>
Enterprise Impact:
2017 PayPal XXE vulnerability allowed internal system access
OWASP Top 10 Quick Reference
Rank | Vulnerability | Test Tool | Remediation |
---|---|---|---|
A01 | Broken Access | Burp Suite | RBAC Implementation |
A02 | Cryptographic Failures | testssl.sh | TLS 1.2+ Enforcement |
A03 | Injection | SQLmap | Prepared Statements |
5. Emerging Web Threats
API Security
Broken object level authorization
Tool: Postman, Burp SuiteWeb3 Vulnerabilities
Smart contract reentrancy
Solution: Slither, MythXServerless Attacks
Event injection in Lambda
Defense: Input validationWeb App Hardening Checklist
✓ Implement WAF (ModSecurity, Cloudflare)
✓ Conduct DAST/SAST scans weekly
✓ Enforce CSP headers
✓ Train developers on secure coding
Chief Security Architect Insight: The 2023 OWASP Benchmark shows applications with regular security testing reduce vulnerabilities by 78%. Effective web security requires both automated scanning (DAST/SAST) and manual penetration testing for business logic flaws.
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