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
1@Component
2public class JwtAuthFilter extends OncePerRequestFilter {
3  private final JwtService jwtService;
4
5  public JwtAuthFilter(JwtService jwtService) {
6    this.jwtService = jwtService;
7  }
8
9  @Override
10  protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response,
11      FilterChain chain) throws ServletException, IOException {
12    String header = request.getHeader(HttpHeaders.AUTHORIZATION);
13    if (header != null && header.startsWith("Bearer ")) {
14      String token = header.substring(7);
15      Authentication auth = jwtService.authenticate(token);
16      SecurityContextHolder.getContext().setAuthentication(auth);
17    }
18    chain.doFilter(request, response);
19  }
20}

Authorization

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

java
1@RestController
2@RequestMapping("/api/admin")
3public class AdminController {
4
5  @PreAuthorize("hasRole('ADMIN')")
6  @GetMapping("/users")
7  public List<UserDto> listUsers() {
8    return userService.findAll();
9  }
10
11  @PreAuthorize("@authz.isOwner(#id, authentication)")
12  @DeleteMapping("/users/{id}")
13  public ResponseEntity<Void> deleteUser(@PathVariable Long id) {
14    userService.delete(id);
15    return ResponseEntity.noContent().build();
16  }
17}

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

java
1// BAD: No validation
2@PostMapping("/users")
3public User createUser(@RequestBody UserDto dto) {
4  return userService.create(dto);
5}
6
7// GOOD: Validated DTO
8public record CreateUserDto(
9    @NotBlank @Size(max = 100) String name,
10    @NotBlank @Email String email,
11    @NotNull @Min(0) @Max(150) Integer age
12) {}
13
14@PostMapping("/users")
15public ResponseEntity<UserDto> createUser(@Valid @RequestBody CreateUserDto dto) {
16  return ResponseEntity.status(HttpStatus.CREATED)
17      .body(userService.create(dto));
18}

SQL Injection Prevention

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

java
1// BAD: String concatenation in native query
2@Query(value = "SELECT * FROM users WHERE name = '" + name + "'", nativeQuery = true)
3
4// GOOD: Parameterized native query
5@Query(value = "SELECT * FROM users WHERE name = :name", nativeQuery = true)
6List<User> findByName(@Param("name") String name);
7
8// GOOD: Spring Data derived query (auto-parameterized)
9List<User> findByEmailAndActiveTrue(String email);

Password Encoding

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

java
1@Bean
2public PasswordEncoder passwordEncoder() {
3  return new BCryptPasswordEncoder(12); // cost factor 12
4}
5
6// In service
7public User register(CreateUserDto dto) {
8  String hashedPassword = passwordEncoder.encode(dto.password());
9  return userRepository.save(new User(dto.email(), hashedPassword));
10}

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

java
1http
2  .csrf(csrf -> csrf.disable())
3  .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

yaml
1# BAD: Hardcoded in application.yml
2spring:
3  datasource:
4    password: mySecretPassword123
5
6# GOOD: Environment variable placeholder
7spring:
8  datasource:
9    password: ${DB_PASSWORD}
10
11# GOOD: Spring Cloud Vault integration
12spring:
13  cloud:
14    vault:
15      uri: https://vault.example.com
16      token: ${VAULT_TOKEN}

Security Headers

java
1http
2  .headers(headers -> headers
3    .contentSecurityPolicy(csp -> csp
4      .policyDirectives("default-src 'self'"))
5    .frameOptions(HeadersConfigurer.FrameOptionsConfig::sameOrigin)
6    .xssProtection(Customizer.withDefaults())
7    .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

java
1@Bean
2public CorsConfigurationSource corsConfigurationSource() {
3  CorsConfiguration config = new CorsConfiguration();
4  config.setAllowedOrigins(List.of("https://app.example.com"));
5  config.setAllowedMethods(List.of("GET", "POST", "PUT", "DELETE"));
6  config.setAllowedHeaders(List.of("Authorization", "Content-Type"));
7  config.setAllowCredentials(true);
8  config.setMaxAge(3600L);
9
10  UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
11  source.registerCorsConfiguration("/api/**", config);
12  return source;
13}
14
15// In SecurityFilterChain:
16http.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

java
1// Using Bucket4j for per-endpoint rate limiting
2@Component
3public class RateLimitFilter extends OncePerRequestFilter {
4  private final Map<String, Bucket> buckets = new ConcurrentHashMap<>();
5
6  private Bucket createBucket() {
7    return Bucket.builder()
8        .addLimit(Bandwidth.classic(100, Refill.intervally(100, Duration.ofMinutes(1))))
9        .build();
10  }
11
12  @Override
13  protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response,
14      FilterChain chain) throws ServletException, IOException {
15    String clientIp = request.getRemoteAddr();
16    Bucket bucket = buckets.computeIfAbsent(clientIp, k -> createBucket());
17
18    if (bucket.tryConsume(1)) {
19      chain.doFilter(request, response);
20    } else {
21      response.setStatus(HttpStatus.TOO_MANY_REQUESTS.value());
22      response.getWriter().write("{\"error\": \"Rate limit exceeded\"}");
23    }
24  }
25}

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.