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.