Quarkus Security Review

Best practices for securing Quarkus applications with authentication, authorization, and input validation.

When to Activate

• Adding authentication (JWT, OIDC, Basic Auth)
• Implementing authorization with @RolesAllowed or SecurityIdentity
• Validating user input (Bean Validation, custom validators)
• Configuring CORS or security headers
• Managing secrets (Vault, environment variables, config sources)
• Adding rate limiting or brute-force protection
• Scanning dependencies for CVEs
• Working with MicroProfile JWT or SmallRye JWT

Authentication

JWT Authentication

// Resource protected with JWT
@Path("/api/protected")
@Authenticated
public class ProtectedResource {

  @Inject
  JsonWebToken jwt;

  @Inject
  SecurityIdentity securityIdentity;

  @GET
  public Response getData() {
    String username = jwt.getName();
    Set<String> roles = jwt.getGroups();
    return Response.ok(Map.of(
        "username", username,
        "roles", roles,
        "principal", securityIdentity.getPrincipal().getName()
    )).build();
  }
}

Configuration (application.properties):

mp.jwt.verify.publickey.location=publicKey.pem
mp.jwt.verify.issuer=https://auth.example.com

# OIDC
quarkus.oidc.auth-server-url=https://auth.example.com/realms/myrealm
quarkus.oidc.client-id=backend-service
quarkus.oidc.credentials.secret=${OIDC_SECRET}

Custom Authentication Filter

@Provider
@Priority(Priorities.AUTHENTICATION)
public class CustomAuthFilter implements ContainerRequestFilter {

  @Inject
  SecurityIdentity identity;

  @Override
  public void filter(ContainerRequestContext requestContext) {
    String authHeader = requestContext.getHeaderString(HttpHeaders.AUTHORIZATION);

    // Reject immediately if header is absent or malformed
    if (authHeader == null || !authHeader.startsWith("Bearer ")) {
      requestContext.abortWith(Response.status(Response.Status.UNAUTHORIZED).build());
      return;
    }

    String token = authHeader.substring(7);
    if (!validateToken(token)) {
      requestContext.abortWith(Response.status(Response.Status.UNAUTHORIZED).build());
    }
  }

  private boolean validateToken(String token) {
    // Token validation logic
    return true;
  }
}

Authorization

Role-Based Access Control

@Path("/api/admin")
@RolesAllowed("ADMIN")
public class AdminResource {

  @GET
  @Path("/users")
  public List<UserDto> listUsers() {
    return userService.findAll();
  }

  @DELETE
  @Path("/users/{id}")
  @RolesAllowed({"ADMIN", "SUPER_ADMIN"})
  public Response deleteUser(@PathParam("id") Long id) {
    userService.delete(id);
    return Response.noContent().build();
  }
}

@Path("/api/users")
public class UserResource {

  @Inject
  SecurityIdentity securityIdentity;

  @GET
  @Path("/{id}")
  @RolesAllowed("USER")
  public Response getUser(@PathParam("id") Long id) {
    // Check ownership
    if (!securityIdentity.hasRole("ADMIN") &&
        !isOwner(id, securityIdentity.getPrincipal().getName())) {
      return Response.status(Response.Status.FORBIDDEN).build();
    }
    return Response.ok(userService.findById(id)).build();
  }

  private boolean isOwner(Long userId, String username) {
    return userService.isOwner(userId, username);
  }
}

Programmatic Security

@ApplicationScoped
public class SecurityService {

  @Inject
  SecurityIdentity securityIdentity;

  public boolean canAccessResource(Long resourceId) {
    if (securityIdentity.isAnonymous()) {
      return false;
    }

    if (securityIdentity.hasRole("ADMIN")) {
      return true;
    }

    String userId = securityIdentity.getPrincipal().getName();
    return resourceRepository.isOwner(resourceId, userId);
  }
}

Input Validation

Bean Validation

// BAD: No validation
@POST
public Response createUser(UserDto dto) {
  return Response.ok(userService.create(dto)).build();
}

// GOOD: Validated DTO
public record CreateUserDto(
    @NotBlank @Size(max = 100) String name,
    @NotBlank @Email String email,
    @NotNull @Min(18) @Max(150) Integer age,
    @Pattern(regexp = "^\\+?[1-9]\\d{1,14}$") String phone
) {}

@POST
@Path("/users")
public Response createUser(@Valid CreateUserDto dto) {
  User user = userService.create(dto);
  return Response.status(Response.Status.CREATED).entity(user).build();
}

Custom Validators

@Target({ElementType.FIELD, ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)

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