Bola Idor in Echo Go (Go)

In Echo Go, an API framework for Go, a BOLA (Broken Object Level Authorization) vulnerability arises when an authenticated user can access resources belonging to other users without proper authorization checks. This typically occurs when API endpoints rely solely on ID-based routing without verifying ownership. For example, consider an endpoint /api/v1/orders/{orderID} that returns an order by ID. If the application does not validate that the requesting user is the actual owner of orderID, any authenticated user can retrieve or modify another user's order by simply changing the ID in the URL. This exposes sensitive data and violates the principle of object-level authorization. The vulnerability is amplified when combined with Go's concurrency model and Echo's routing flexibility, which make it easy to implement endpoints that lack explicit ownership validation.

BOLA vulnerabilities are particularly dangerous in APIs because they allow privilege escalation without requiring additional permissions. In Go, the common pattern of using request parameters directly in structs or handlers can lead to insecure direct object references (IDOR) if not carefully guarded. The risk is not limited to read operations; attackers can often modify resources if the backend does not enforce strict access controls. This issue maps directly to OWASP API Top 10 category Broken Object Level Authorization (A01_2023). Real-world examples include cases where CVE-2023-XXXXX was assigned to similar flaws in popular frameworks, though the specific exploit depends on implementation details rather than the framework itself.

middleBrick detects such issues by analyzing API endpoints for predictable object identifier usage without proper authorization checks. When scanning an Echo Go endpoint like /api/v1/users/{id}/profile, the scanner checks whether the request path contains user-supplied identifiers that could lead to unauthorized access. If the response includes sensitive data without requiring additional authorization tokens or headers that prove ownership, middleBrick flags this as a high-severity BOLA risk. The scanner also correlates findings with OpenAPI specifications to determine if the endpoint's $ref definitions indicate expected authorization flows that are missing in practice. This self-service scanning process takes 5–15 seconds and requires only a URL input, making it ideal for developers who want immediate feedback on security posture without setting up complex test environments.

To remediate BOLA in Echo Go, developers must explicitly verify resource ownership before processing requests. This involves checking that the authenticated user has permission to access the requested resource. Below is a secure implementation example using Echo and Go's standard library:

package main

import (
	"net/http"
	"strconv"

	"example.com/project/model"
	"example.com/project/auth"
)

func OrderHandler(c echo.Context) error {
	user := auth.GetCurrentUser(c)
	orderIDStr := c.Param("orderID")
	orderID, _ := strconv.Atoi(orderIDStr)

	// Securely fetch order and verify ownership
	order, err := model.GetOrderByID(orderID)
	if err != nil {
		return c.JSON(http.StatusNotFound, {"error": "order not found"})
	}

	// Critical check: ensure user owns this order
	if order.UserID != user.ID {
		return c.JSON(http.StatusForbidden, {"error": "access denied"})
	}

	return c.JSON(http.StatusOK, order)
}

This code demonstrates proper object-level authorization by comparing the order's owner ID with the currently authenticated user's ID. The auth.GetCurrentUser function should extract the user from a JWT or session token, and model.GetOrderByID retrieves the order from the database. The key security step is the explicit check order.UserID != user.ID, which prevents unauthorized access. Developers should also implement similar checks for update and delete operations. Additionally, using UUIDs instead of sequential integers for identifiers can reduce the risk of enumeration attacks, though the core fix remains the authorization check itself. This pattern aligns with OWASP recommendations for API security and is detectable by middleBrick during scanning, which will no longer report a BOLA finding once such checks are properly implemented.