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Automated Security Protocol

How to fix Insecure API Management
in Plug

Executive Summary

Insecure API management in Elixir/Plug environments typically manifests as missing authentication pipelines, lack of rate limiting, and exposure of sensitive internal metadata. If your Plug router doesn't enforce a 'fail-closed' security posture at the pipeline level, you are inviting credential stuffing and unauthorized data exfiltration.

The Vulnerable Pattern

VULNERABLE CODE
defmodule MyApp.Router do
  use Plug.Router
  plug :match
  plug :dispatch

VULNERABLE: No authentication or rate limiting applied to the API endpoint


get “/api/v1/user_data/:id” do
user = MyApp.DB.get_user(id)
send_resp(conn, 200, Jason.encode!(user))
end
end

The Secure Implementation

To harden the API, we implement a dedicated AuthPlug that validates Bearer tokens and invokes `halt(conn)` to prevent further execution on failure. We also integrate a RateLimiter plug to mitigate DoS and brute-force attempts. By moving security logic into the pipeline, we ensure that the business logic is never reached unless the request satisfies the security policy.

SECURE CODE
defmodule MyApp.AuthPlug do
  import Plug.Conn
  def init(opts), do: opts
  def call(conn, _opts) do
    case get_req_header(conn, "authorization") do
      ["Bearer " <> token] -> 
        if MyApp.Auth.valid_token?(token), do: conn, else: unauthorized(conn)
      _ -> unauthorized(conn)
    end
  end
  defp unauthorized(conn) do
    conn |> send_resp(401, "Unauthorized") |> halt()
  end
end

defmodule MyApp.Router do
use Plug.Router


SECURE: Global rate limiting and scoped authentication


plug MyApp.Plugs.RateLimiter, limit: 100, window: 60
plug :match
plug :dispatch


get “/api/v1/user_data/:id” do
conn
|> MyApp.AuthPlug.call([])
|> case do
%{halted: true} = conn -> conn
conn ->
user = MyApp.DB.get_user(id)
send_resp(conn, 200, Jason.encode!(user))
end
end
end

System Alert • ID: 5968
Target: Plug API
Potential Vulnerability

Your Plug API might be exposed to Insecure API Management

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

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