Overview Theory is essential—but real-world examples show how vulnerabilities become breaches. This lesson explores high-impact vulnerabilities that have been actively exploited across websites, applications, and infrastructure. Each case illustrates how a simple weakness can escalate into a full-blown incident.

1. SQL Injection (SQLi)

Description: Attackers inject malicious SQL statements into input fields to manipulate backend databases. Impact: Data theft, unauthorized access, deletion of records, or full database compromise. Real-World Note: SQLi remains a top OWASP threat. In 2024, a major e-commerce platform was breached via a vulnerable search bar, exposing millions of customer records. Mitigation: Use parameterized queries and input sanitization.

2. Cross-Site Scripting (XSS)

Description: Malicious scripts are injected into web pages and executed in users’ browsers. Impact: Session hijacking, credential theft, redirection to malicious sites. Real-World Note: A popular forum platform was exploited via stored XSS in user profiles, allowing attackers to steal admin sessions. Mitigation: Sanitize user input and use Content Security Policy (CSP) headers.

3. Outdated CMS Components (e.g., WordPress Plugins)

Description: Unpatched plugins or themes contain known vulnerabilities. Impact: Remote code execution, malware injection, site defacement. Real-World Note: Sucuri’s 2025 Threat Report confirms that outdated WordPress plugins remain the leading cause of site infections. Mitigation: Enable auto-updates and monitor plugin changelogs.

4. Default or Weak Credentials

Description: Using default usernames (e.g., “admin”) or weak passwords. Impact: Unauthorized access, privilege escalation, full site takeover. Real-World Note: A 2025 ransomware campaign targeted exposed admin panels with default credentials, compromising hundreds of small business sites. Mitigation: Enforce strong password policies and enable multi-factor authentication (MFA).

5. Misconfigured Databases

Description: Databases exposed to the internet without authentication or encryption. Impact: Direct access to sensitive data, often without triggering alerts. Real-World Note: In early 2025, a misconfigured MongoDB instance leaked over 2 million patient records due to lack of access controls. Mitigation: Restrict access to internal networks and require authentication.

6. Insecure File Uploads

Description: Upload forms that allow execution of malicious files (e.g., .php, .exe). Impact: Remote shell access, malware deployment, server compromise. Real-World Note: A travel booking site was breached via an image upload field that allowed .php files, leading to full server access. Mitigation: Validate file types, use sandboxed directories, and disable execution permissions.

Key Takeaways

• Vulnerabilities like SQLi, XSS, and outdated plugins are actively exploited—not theoretical risks
• Weak credentials and misconfigurations remain top entry points for attackers
• Real-world breaches often stem from simple oversights
• Mitigation requires proactive patching, secure defaults, and layered defenses