walterfan/lazy-ai-primer/springboot-security

Spring Boot Security Review

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

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

@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
• Use @PreAuthorize("hasRole('ADMIN')") or @PreAuthorize("@authz.canEdit(#id)")
• Deny by default; expose only required scopes

Input Validation

• Use Bean Validation with @Valid on controllers
• Apply constraints on DTOs: @NotBlank, @Email, @Size, custom validators
• Sanitize any HTML with a whitelist before rendering

SQL Injection Prevention

• Use Spring Data repositories or parameterized queries
• For native queries, use :param bindings; never concatenate strings

CSRF Protection

• For browser session apps, keep CSRF enabled; include token in forms/headers
• For pure APIs with Bearer tokens, disable CSRF and rely on stateless auth

http
  .csrf(csrf -> csrf.disable())
  .sessionManagement(sm -> sm.sessionCreationPolicy(SessionCreationPolicy.STATELESS));

Secrets Management

• No secrets in source; load from env or vault
• Keep application.yml free of credentials; use placeholders
• Rotate tokens and DB credentials regularly

Security Headers

http
  .headers(headers -> headers
    .contentSecurityPolicy(csp -> csp
      .policyDirectives("default-src 'self'"))
    .frameOptions(HeadersConfigurer.FrameOptionsConfig::sameOrigin)
    .xssProtection(Customizer.withDefaults())
    .referrerPolicy(rp -> rp.policy(ReferrerPolicyHeaderWriter.ReferrerPolicy.NO_REFERRER)));

Rate Limiting

• Apply Bucket4j or gateway-level limits on expensive endpoints
• Log and alert on bursts; return 429 with retry hints

Dependency Security

• Run OWASP Dependency Check / Snyk in CI
• Keep Spring Boot and Spring Security on supported versions
• Fail builds on known CVEs

Logging and PII

• Never log secrets, tokens, passwords, or full PAN data
• Redact sensitive fields; use structured JSON logging

File Uploads

• Validate size, content type, and extension
• Store outside web root; scan if required

Checklist Before Release

• [ ] Auth tokens validated and expired correctly
• [ ] Authorization guards on every sensitive path
• [ ] All inputs validated and sanitized
• [ ] No string-concatenated SQL
• [ ] CSRF posture correct for app type
• [ ] Secrets externalized; none committed
• [ ] Security headers configured
• [ ] Rate limiting on APIs
• [ ] Dependencies scanned and up to date
• [ ] Logs free of sensitive data

Remember: Deny by default, validate inputs, least privilege, and secure-by-configuration first.