Arp Spoofing in Adonisjs with Basic Auth

Arp spoofing is a Layer 2 attack where an adversary sends falsified ARP messages to associate their MAC address with the IP of a legitimate host, such as your API server or a gateway. In an AdonisJS application that relies on HTTP Basic Auth over unencrypted HTTP, this combination creates a critical exposure: credentials are sent in an easily recoverable format (Base64), and the network path can be manipulated by an attacker conducting an active man-in-the-middle (MITM) interception.

When a client submits Basic Auth credentials to an AdonisJS endpoint over HTTP, the header looks like Authorization: Basic base64(username:password). If an attacker successfully spoofs ARP entries on the local network segment—commonly in environments without switch port security or static ARP—they can redirect traffic through their machine. Because the traffic is not encrypted, the attacker can capture the Base64-encoded credentials, decode them offline, and gain valid access to the AdonisJS application. The framework itself does not mitigate this; the risk arises from using Basic Auth without transport-layer protection in an environment susceptible to ARP spoofing.

Even if the AdonisJS server terminates TLS, an attacker who can still force a client to communicate over HTTP (e.g., via SSL stripping or leveraging mixed-content scenarios) can exploit ARP spoofing to intercept credentials. MiddleBrick’s scans detect unauthenticated endpoints and flag weak transport configurations; scanning your AdonisJS API can reveal whether Basic Auth is exposed over non-TLS channels and highlight opportunities to strengthen the deployment topology.

To mitigate ARP spoofing risks when using Basic Auth in AdonisJS, the primary defense is enforcing HTTPS so that credentials are encrypted in transit. Additionally, avoid storing or transmitting passwords in clear text; use framework facilities to manage secure authentication flows. Below are concrete examples demonstrating secure practices.

1. Enforce HTTPS and redirect HTTP to HTTPS

Ensure your AdonisJS server is configured to accept only HTTPS connections. When deploying behind a proxy or load balancer, set trusted headers appropriately and enable strict transport policies.

// start/hooks.ts or server entry
import { defineConfig } from '@adonisjs/core/app'

export default defineConfig({
  https: {
    key: '/path/to/key.pem',
    cert: '/path/to/cert.pem',
  },
})

2. Use environment-based configuration for Basic Auth credentials

Never hardcode credentials. Load them from environment variables and validate them at runtime.

// .env
API_BASIC_USER=api_reader
API_BASIC_PASS=SuperSecretPassw0rd!

// start/kernel.ts or a dedicated auth provider
import Env from '@ioc:Adonis/Core/Env'

const BASIC_AUTH_USER = Env.get('API_BASIC_USER')
const BASIC_AUTH_PASS = Env.get('API_BASIC_PASS')

3. Implement a secure Basic Auth middleware that validates credentials on each request

Create middleware that checks the Authorization header and rejects unauthenticated requests without exposing details in error messages.

// start/middleware/basic_auth.ts
import { Exception } from '@adonisjs/core/build/standalone'

export default async function basicAuth(ctx, next) {
  const authHeader = ctx.request.header('authorization')
  if (!authHeader || !authHeader.startsWith('Basic ')) {
    ctx.response.unauthorized({ message: 'Unauthorized' })
    return
  }

  const base64 = authHeader.split(' ')[1]
  const decoded = Buffer.from(base64, 'base64').toString('utf-8')
  const [username, password] = decoded.split(':')

  const VALID_USER = Env.get('API_BASIC_USER')
  const VALID_PASS = Env.get('API_BASIC_PASS')

  if (username !== VALID_USER || password !== VALID_PASS) {
    ctx.response.unauthorized({ message: 'Unauthorized' })
    return
  }

  await next()
}

4. Register middleware and apply it to protected routes

Apply the middleware only to routes that require protection, minimizing exposure.

// start/routes.ts
import Route from '@ioc:Adonis/Core/Route'
import basicAuth from 'App/Middleware/basic_auth'

Route.group(() => {
  Route.get('/secure/data', async ({ response }) => {
    return response.send({ secret: 'only over HTTPS with valid Basic Auth' })
  }).middleware([basicAuth])
}).prefix('api/v1')

5. Complementary practices

• Use strong, complex passwords for Basic Auth credentials and rotate them regularly.
• Employ network-level protections such as VLAN segmentation and ARP monitoring to reduce spoofing feasibility.
• Where possible, prefer token-based authentication (e.g., JWT) over Basic Auth to avoid repeated transmission of credentials.

MiddleBrick’s scans can validate whether your endpoints require authentication and whether findings such as BOLA/IDOR or unsafe consumption patterns intersect with Basic Auth usage, helping you prioritize remediation.