Fiber API Security

Fiber is a Go web framework inspired by Express.js that prioritizes speed and simplicity. Out of the box, Fiber provides zero security configuration — which means developers must actively implement protections. The framework handles HTTP routing efficiently but doesn't enforce authentication, rate limiting, or input validation by default. This minimalist approach gives developers flexibility but creates security gaps that malicious actors can exploit.

Fiber's default middleware stack includes only basic request parsing and routing. While this keeps applications lightweight, it leaves APIs vulnerable to common attacks like brute force attempts, injection attacks, and unauthorized data access. The framework's performance optimizations (using Fasthttp under the hood) don't include security features — developers must layer these protections manually.

1. Missing Rate Limiting
Fiber applications without rate limiting are vulnerable to brute force attacks and API abuse. An attacker can send unlimited requests to authentication endpoints, enumeration endpoints, or any other resource. This not only risks account compromise but can also lead to denial of service through resource exhaustion.

2. Unprotected Admin Routes
Many Fiber applications expose administrative endpoints without proper authentication or authorization. Developers often forget to secure /admin, /metrics, or /debug routes, allowing anyone to access sensitive operational data or perform administrative actions.

3. Insecure Default Headers
Fiber doesn't set security headers by default. Without headers like Content-Security-Policy, X-Frame-Options, or Strict-Transport-Security, applications are vulnerable to clickjacking, cross-site scripting, and man-in-the-middle attacks.

4. Insufficient Input Validation
Fiber's JSON parsing accepts any valid JSON without schema validation. Attackers can send malformed or malicious payloads that cause unexpected behavior, database errors, or even remote code execution in vulnerable applications.

5. Missing CORS Configuration
Without proper CORS configuration, Fiber APIs may allow cross-origin requests from any domain. This exposes APIs to unauthorized access from malicious websites and can lead to data exfiltration or abuse of authenticated sessions.

1. Implement Rate Limiting
Use a middleware like fiber/v2/middleware/rate to prevent abuse:

import "github.com/gofiber/fiber/v2/middleware/rate"

app.Use(rate.New(rate.Config{
    Filter: func(c *fiber.Ctx) bool {
        // Skip rate limiting for health checks
        return c.Path() == "/health"
    },
    TimeSlice: 10 * time.Second,
    Limit: 100,
}))

2. Add Security Headers
Configure essential security headers using middleware:

import "github.com/gofiber/fiber/v2/middleware/helmet"

app.Use(helmet.New())

3. Validate All Inputs
Never trust client input. Use validation libraries and define strict schemas:

import "github.com/go-playground/validator/v10"

type LoginRequest struct {
    Email    string `json:"email" validate:"required,email"`
    Password string `json:"password" validate:"required,min=8"`
}

func loginHandler(c *fiber.Ctx) error {
    var req LoginRequest
    if err := c.BodyParser(&req); err != nil {
        return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "Invalid request"})
    }
    
    if err := validator.New().Struct(req); err != nil {
        return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": err.Error()})
    }
    
    // Process login
    return c.JSON(fiber.Map{"message": "Login successful"})
}

4. Secure Authentication Endpoints
Implement proper authentication with rate limiting on login attempts:

app.Post("/login", rate.New(rate.Config{Limit: 5, TimeSlice: 1 * time.Minute}), loginHandler)

5. Configure CORS Properly
Restrict cross-origin requests to trusted domains:

import "github.com/gofiber/fiber/v2/middleware/cors"

app.Use(cors.New(cors.Config{
    AllowOrigins: "https://yourdomain.com",
    AllowMethods: "GET,POST,PUT,DELETE",
    AllowHeaders: "Origin, Content-Type, Accept, Authorization",
}))

6. Scan Your API
Before deploying, scan your Fiber API with middleBrick to identify security vulnerabilities. The free tier lets you scan 3 APIs per month to check for authentication bypass, injection flaws, and misconfigurations that automated tools can catch.