Broken Access Control in Echo Go

Broken Access Control in Echo Go applications typically manifests through several Echo-specific patterns. The most common vulnerability occurs when developers forget to implement middleware authentication checks on route handlers, allowing unauthenticated users to access restricted endpoints.

A classic example is missing authentication middleware on admin routes:

e.GET("/admin/users", func(c echo.Context) error {
    // No authentication check
    users := getUsersFromDB()
    return c.JSON(http.StatusOK, users)
})

Another Echo-specific pattern is improper use of path parameters without validation. Consider this vulnerable endpoint:

e.GET("/users/:id", func(c echo.Context) error {
    id := c.Param("id")
    user := getUserByID(id) // No ownership verification
    return c.JSON(http.StatusOK, user)
})

This allows any authenticated user to access any other user's data by simply changing the ID parameter—a textbook BOLA (Broken Object Level Authorization) vulnerability.

Echo's flexible context binding can also introduce vulnerabilities. Developers often bind request data without proper validation:

type UpdateRequest struct {
    Email string `json:"email"`
    Role  string `json:"role"`
}

e.PUT("/users/:id", func(c echo.Context) error {
    id := c.Param("id")
    var req UpdateRequest
    if err := c.Bind(&req); err != nil {
        return err
    }
    // Missing authorization check before update
    updateUser(id, req.Email, req.Role)
    return c.JSON(http.StatusOK, "success")
})

The above code allows any authenticated user to potentially escalate privileges by changing the Role field.

Detecting Broken Access Control in Echo applications requires both static analysis and dynamic testing. Static analysis can identify missing middleware patterns, while dynamic testing validates the actual behavior.

For static detection, look for Echo route handlers missing authentication middleware. A simple grep pattern can identify vulnerable routes:

# Find Echo routes without auth middleware
grep -r "e\.[A-Z]" . | grep -v "middleware" | grep -v "auth"

Dynamic testing with middleBrick provides comprehensive coverage. The scanner automatically tests Echo applications for BOLA vulnerabilities by:

• Modifying path parameters to access other users' resources
• Testing different user roles against restricted endpoints
• Checking for missing authentication on admin routes
• Verifying proper authorization headers are required

middleBrick's Echo-specific detection includes checking for common Echo patterns like:

// Vulnerable: No auth middleware
func main() {
    e := echo.New()
    e.GET("/admin", adminHandler)
    e.Start(":8080")
}

// Secure: Auth middleware applied
func main() {
    e := echo.New()
    e.Use(middleware.JWTWithConfig(middleware.JWTConfig{
        SigningKey: []byte("secret"),
    }))
    e.GET("/admin", adminHandler)
    e.Start(":8080")
}

middleBrick also tests Echo's context binding vulnerabilities by sending modified request bodies and checking if the server processes unauthorized changes.

Remediating Broken Access Control in Echo Go applications requires a multi-layered approach using Echo's built-in features and best practices.

First, implement proper authentication middleware at the application level:

func main() {
    e := echo.New()
    
    // Global JWT middleware
    e.Use(middleware.JWTWithConfig(middleware.JWTConfig{
        SigningKey: []byte("your-secret-key"),
    }))
    
    // Role-based authorization middleware
    e.Use(roleAuthMiddleware())
    
    e.GET("/users/:id", getUserHandler)
    e.PUT("/users/:id", updateUserHandler)
    e.GET("/admin", adminHandler)
    
    e.Start(":8080")
}

// Role-based authorization middleware
func roleAuthMiddleware() echo.MiddlewareFunc {
    return func(next echo.HandlerFunc) echo.HandlerFunc {
        return func(c echo.Context) error {
            user := c.Get("user").(*jwt.Token)
            claims := user.Claims.(jwt.MapClaims)
            role := claims["role"].(string)
            
            // Check if user has permission for this endpoint
            if !hasPermission(c.Request().URL.Path, role) {
                return echo.NewHTTPError(http.StatusForbidden, "Insufficient permissions")
            }
            return next(c)
        }
    }
}

Second, implement proper ownership verification in data access functions:

func getUserHandler(c echo.Context) error {
    id := c.Param("id")
    userID, _ := strconv.Atoi(id)
    
    // Get authenticated user ID from JWT claims
    user := c.Get("user").(*jwt.Token)
    claims := user.Claims.(jwt.MapClaims)
    authUserID := int(claims["id"].(float64))
    
    // Verify ownership
    if authUserID != userID {
        return echo.NewHTTPError(http.StatusForbidden, "Access denied")
    }
    
    user := getUserFromDB(userID)
    return c.JSON(http.StatusOK, user)
}

Third, use Echo's parameter binding with validation:

type UpdateRequest struct {
    Email string `json:"email" validate:"email"`
    Role  string `json:"role" validate:"omitempty,eq=USER|eq=ADMIN"`
}

func updateUserHandler(c echo.Context) error {
    id := c.Param("id")
    userID, _ := strconv.Atoi(id)
    
    // Get authenticated user
    user := c.Get("user").(*jwt.Token)
    claims := user.Claims.(jwt.MapClaims)
    authUserID := int(claims["id"].(float64))
    authRole := claims["role"].(string)
    
    // Only allow users to update their own profile or admins to update any profile
    if authUserID != userID && authRole != "ADMIN" {
        return echo.NewHTTPError(http.StatusForbidden, "Access denied")
    }
    
    var req UpdateRequest
    if err := c.Bind(&req); err != nil {
        return err
    }
    
    // Validate request
    if err := c.Validate(req); err != nil {
        return echo.NewHTTPError(http.StatusBadRequest, err.Error())
    }
    
    // Only admins can change roles
    if req.Role != "" && authRole != "ADMIN" {
        return echo.NewHTTPError(http.StatusForbidden, "Only admins can change roles")
    }
    
    updateUser(userID, req.Email, req.Role)
    return c.JSON(http.StatusOK, "success")
}