Springboot Security

# Spring Boot Security Review

Use when adding auth, handling input, creating endpoints, or dealing with secrets.

## When to Activate

- Adding authentication (JWT, OAuth2, session-based)
- Implementing authorization (@PreAuthorize, role-based access)
- Validating user input (Bean Validation, custom validators)
- Configuring CORS, CSRF, or security headers
- Managing secrets (Vault, environment variables)
- Adding rate limiting or brute-force protection
- Scanning dependencies for CVEs

## Authentication

- Prefer stateless JWT or opaque tokens with revocation list
- Use `httpOnly`, `Secure`, `SameSite=Strict` cookies for sessions
- Validate tokens with `OncePerRequestFilter` or resource server

```java
@Component
public class JwtAuthFilter extends OncePerRequestFilter {
  private final JwtService jwtService;

  public JwtAuthFilter(JwtService jwtService) {
    this.jwtService = jwtService;
  }

  @Override
  protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response,
      FilterChain chain) throws ServletException, IOException {
    String header = request.getHeader(HttpHeaders.AUTHORIZATION);
    if (header != null && header.startsWith("Bearer ")) {
      String token = header.substring(7);
      Authentication auth = jwtService.authenticate(token);
      SecurityContextHolder.getContext().setAuthentication(auth);
    }
    chain.doFilter(request, response);
  }
}
```

## Authorization

- Enable method security: `@EnableMethodSecurity`