Security Review

Review Checklist

Authentication

• Strong password requirements enforced
• MFA implemented for sensitive operations
• Session tokens are cryptographically secure
• Session timeout is appropriate
• Logout properly invalidates session

Authorization

• Access controls checked server-side
• Least privilege principle applied
• Role-based access properly implemented
• Direct object references validated

Input Validation

• All input validated server-side
• Input type and length checked
• Special characters properly handled
• File uploads validated and restricted

Output Encoding

• HTML output properly encoded
• JSON responses use proper content type
• Error messages don't leak information

Cryptography

• Strong algorithms used (AES-256, RSA-2048+)
• No custom crypto implementations
• Keys properly managed
• TLS 1.2+ enforced

Error Handling

• Exceptions handled gracefully
• Error messages don't expose internals
• Failed operations logged

Logging

• Security events logged
• Sensitive data not logged
• Logs protected from tampering

Code Patterns to Flag (Java)

SQL Injection

// ❌ DANGER - SQL Injection
String query = "SELECT * FROM users WHERE id = " + userId;
jdbcTemplate.queryForObject(query, User.class);

// ✅ SAFE - Use JPA or parameterized queries
@Query("SELECT u FROM User u WHERE u.id = :id")
Optional<User> findById(@Param("id") Long id);

XSS (Cross-Site Scripting)

// ❌ DANGER - Unescaped output in templates
@GetMapping("/profile")
public String profile(Model model, @RequestParam String name) {
    model.addAttribute("name", name); // If rendered without escaping
    return "profile";
}

// ✅ SAFE - Use Thymeleaf with proper escaping
<!-- Thymeleaf auto-escapes by default -->
<p th:text="${name}">Name here</p>

// ✅ SAFE - Manual escaping if needed
import org.springframework.web.util.HtmlUtils;
String safe = HtmlUtils.htmlEscape(userInput);

Hardcoded Secrets

// ❌ DANGER - Hardcoded credentials
public class ApiClient {
    private static final String API_KEY = "sk-abc123...";
    private static final String DB_PASSWORD = "password123";
}

// ✅ SAFE - Use environment variables
@Value("${api.key}")
private String apiKey;

@Value("${spring.datasource.password}")
private String dbPassword;

Insecure Random

// ❌ DANGER - Predictable random for security
Random random = new Random();
String token = String.valueOf(random.nextInt());

// ✅ SAFE - Use SecureRandom for security purposes
SecureRandom secureRandom = new SecureRandom();
byte[] token = new byte[32];
secureRandom.nextBytes(token);
String tokenStr = Base64.getUrlEncoder().encodeToString(token);

Path Traversal

// ❌ DANGER - Path traversal vulnerability
@GetMapping("/files/{filename}")
public ResponseEntity<Resource> getFile(@PathVariable String filename) {
    File file = new File("/uploads/" + filename);
    return ResponseEntity.ok(new FileSystemResource(file));
}

// ✅ SAFE - Validate and sanitize path
@GetMapping("/files/{filename}")
public ResponseEntity<Resource> getFile(@PathVariable String filename) {
    // Reject path traversal attempts
    if (filename.contains("..") || filename.contains("/")) {
        throw new IllegalArgumentException("Invalid filename");
    }

    Path basePath = Paths.get("/uploads").toAbsolutePath().normalize();
    Path filePath = basePath.resolve(filename).normalize();

    // Ensure resolved path is within base directory
    if (!filePath.startsWith(basePath)) {
        throw new SecurityException("Path traversal detected");
    }

    return ResponseEntity.ok(new FileSystemResource(filePath));
}

Security Review Report

## Security Review: [Component]

### Summary
- Critical: [X]
- High: [X]
- Medium: [X]
- Low: [X]

### Findings

#### [CRITICAL] SQL Injection in UserService
**Location**: api/src/main/java/com/example/service/UserService.java:47
**Description**: User input concatenated into SQL query
**Remediation**: Use JPA with named parameters
**Code**:
```java
// Current (vulnerable)
String query = "SELECT * FROM users WHERE email = '" + email + "'";

// ✅ Recommended fix
@Query("SELECT u FROM User u WHERE u.email = :email")
Optional<User> findByEmail(@Param("email") String email);