springboot-security

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Spring Security best practices for authn/authz, validation, CSRF, secrets, headers, rate limiting, and dependency security in Java Spring Boot services.

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

@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

@RestController
@RequestMapping("/api/admin")
public class AdminController {

  @PreAuthorize("hasRole('ADMIN')")
  @GetMapping("/users")
  public List<UserDto> listUsers() {
    return userService.findAll();
  }

  @PreAuthorize("@authz.isOwner(#id, authentication)")
  @DeleteMapping("/users/{id}")
  public ResponseEntity<Void> deleteUser(@PathVariable Long id) {
    userService.delete(id);
    return ResponseEntity.noContent().build();
  }
}

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

// BAD: No validation
@PostMapping("/users")
public User createUser(@RequestBody UserDto dto) {
  return userService.create(dto);
}

// GOOD: Validated DTO
public record CreateUserDto(
    @NotBlank @Size(max = 100) String name,
    @NotBlank @Email String email,
    @NotNull @Min(0) @Max(150) Integer age
) {}

@PostMapping("/users")
public ResponseEntity<UserDto> createUser(@Valid @RequestBody CreateUserDto dto) {
  return ResponseEntity.status(HttpStatus.CREATED)
      .body(userService.create(dto));
}

SQL Injection Prevention

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

// BAD: String concatenation in native query
@Query(value = "SELECT * FROM users WHERE name = '" + name + "'", nativeQuery = true)

// GOOD: Parameterized native query
@Query(value = "SELECT * FROM users WHERE name = :name", nativeQuery = true)
List<User> findByName(@Param("name") String name);

// GOOD: Spring Data derived query (auto-parameterized)
List<User> findByEmailAndActiveTrue(String email);

Password Encoding

Always hash passwords with BCrypt or Argon2 — never store plaintext
Use PasswordEncoder bean, not manual hashing

@Bean
public PasswordEncoder passwordEncoder() {
  return new BCryptPasswordEncoder(12); // cost factor 12
}

// In service
public User register(CreateUserDto dto) {
  String hashedPassword = passwordEncoder.encode(dto.password());
  return userRepository.save(new User(dto.email(), hashedPassword));
}

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

# BAD: Hardcoded in application.yml
spring:
  datasource:
    password: mySecretPassword123

# GOOD: Environment variable placeholder
spring:
  datasource:
    password: ${DB_PASSWORD}

# GOOD: Spring Cloud Vault integration
spring:
  cloud:
    vault:
      uri: https://vault.example.com
      token: ${VAULT_TOKEN}

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)));

CORS Configuration

Configure CORS at the security filter level, not per-controller
Restrict allowed origins — never use * in production

@Bean
public CorsConfigurationSource corsConfigurationSource() {
  CorsConfiguration config = new CorsConfiguration();
  config.setAllowedOrigins(List.of("https://app.example.com"));
  config.setAllowedMethods(List.of("GET", "POST", "PUT", "DELETE"));
  config.setAllowedHeaders(List.of("Authorization", "Content-Type"));
  config.setAllowCredentials(true);
  config.setMaxAge(3600L);

  UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
  source.registerCorsConfiguration("/api/**", config);
  return source;
}

// In SecurityFilterChain:
http.cors(cors -> cors.configurationSource(corsConfigurationSource()));

Rate Limiting

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

// Using Bucket4j for per-endpoint rate limiting
@Component
public class RateLimitFilter extends OncePerRequestFilter {
  private final Map<String, Bucket> buckets = new ConcurrentHashMap<>();

  private Bucket createBucket() {
    return Bucket.builder()
        .addLimit(Bandwidth.classic(100, Refill.intervally(100, Duration.ofMinutes(1))))
        .build();
  }

  @Override
  protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response,
      FilterChain chain) throws ServletException, IOException {
    String clientIp = request.getRemoteAddr();
    Bucket bucket = buckets.computeIfAbsent(clientIp, k -> createBucket());

    if (bucket.tryConsume(1)) {
      chain.doFilter(request, response);
    } else {
      response.setStatus(HttpStatus.TOO_MANY_REQUESTS.value());
      response.getWriter().write("{\"error\": \"Rate limit exceeded\"}");
    }
  }
}

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

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

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