GuardAPI Logo
GuardAPI
Automated Security Protocol

How to fix Insecure API Management
in Phoenix

Executive Summary

Phoenix APIs are often vulnerable to Broken Object Level Authorization (BOLA/IDOR) and weak authentication when developers rely on default pipelines. Insecure API management typically involves exposing internal IDs without ownership verification or failing to enforce rate limiting and token validation at the router level. We need to harden the pipeline and ensure the context layer enforces strict resource scoping.

The Vulnerable Pattern

VULNERABLE CODE
defmodule MyAppWeb.Router do
  use MyAppWeb, :router
  pipeline :api do
    plug :accepts, ["json"]
  end

scope “/api”, MyAppWeb do
pipe_through :api
get “/docs/:id”, DocController, :show
end
end


Controller


def show(conn, %{“id” => id}) do
doc = Library.get_doc!(id) # VULNERABLE: No ownership check
render(conn, “show.json”, doc: doc)
end

The Secure Implementation

The fix involves two layers of defense. First, we implement a dedicated authentication pipeline in the router to ensure every request carries a valid credential (e.g., via Guardian or Phx.Token). Second, we solve the IDOR vulnerability by refactoring the context functions to require the 'current_user' as an argument. Instead of fetching a record by ID alone, we query by ID and user_id, ensuring that even if an attacker guesses a valid UUID, the database will return null if they do not own the resource.

SECURE CODE
defmodule MyAppWeb.Router do
  use MyAppWeb, :router
  pipeline :api do
    plug :accepts, ["json"]
    plug MyAppWeb.Auth.Pipeline # JWT/Token verification
  end

scope “/api”, MyAppWeb do
pipe_through :api
resources “/docs”, DocController, only: [:show]
end
end


Controller


def show(conn, %{“id” => id}) do
user = conn.assigns.current_user


SECURE: Scoped query ensures user owns the document


case Library.get_user_doc(user, id) do
nil -> conn |> put_status(:not_found) |> json(%{error: “Not Found”})
doc -> render(conn, “show.json”, doc: doc)
end
end

System Alert • ID: 4348
Target: Phoenix API
Potential Vulnerability

Your Phoenix API might be exposed to Insecure API Management

74% of Phoenix apps fail this check. Hackers use automated scanners to find this specific flaw. Check your codebase before they do.

RUN FREE SECURITY DIAGNOSTIC
GuardLabs Engine: ONLINE

Free Tier • No Credit Card • Instant Report

Verified by Ghost Labs Security Team

This content is continuously validated by our automated security engine and reviewed by our research team. Ghost Labs analyzes over 500+ vulnerability patterns across 40+ frameworks to provide up-to-date remediation strategies.

About GuardLabs → Follow us on X