Brute Force Attack in Adonisjs with Api Keys

A brute force attack against an AdonisJS API that relies on API keys can occur when the API key is treated as a single-factor credential and no additional protections are applied. In AdonisJS, API keys are commonly validated in an authentication layer, such as an Authenticator provider or via an auth.ts configuration, where the key is looked up in a database or environment-based store. If an endpoint accepts a raw API key in a header (e.g., Authorization: ApiKey {key}) and does not enforce rate limits or lockout policies, an attacker can systematically guess or iterate through valid key formats and observe differences in response behavior.

The vulnerability is exposed when responses differ based on whether the key is valid, absent, or malformed. For example, a 200 OK with data for a valid key, versus a 401 Unauthorized or 404 Not Found for invalid keys, allows an attacker to infer key validity without ever needing to know the key’s associated scope or permissions. This becomes more dangerous when API keys are long-lived or shared across services, as a discovered key can grant access across multiple endpoints.

AdonisJS does not enforce authentication rate limiting by default, so an attacker can send many requests per second, testing many keys or key prefixes. If the application does not implement exponential backoff or token blacklisting after suspicious patterns, the attack surface remains wide. The risk is compounded when the API key is passed in URLs or logs, increasing exposure through referrer headers or server-side logs.

Another contributing factor is the lack of per-key attempt tracking. Without storing failed attempts against a specific key or IP, the system cannot detect or slow down credential probing. Insecure deserialization or improper validation of key formats may also allow malformed keys to bypass checks or trigger server errors that leak stack traces, further aiding an attacker in refining their guesses.

To illustrate, an endpoint that expects an API key in the X-API-Key header and returns different status codes based on validity can be probed as follows, demonstrating how a brute force approach might be structured against an AdonisJS service.

Remediation focuses on reducing the information leaked during authentication and enforcing usage constraints on API keys. In AdonisJS, you can customize the authentication pipeline to return uniform responses and integrate rate limiting at the route or middleware level.

First, ensure your authentication logic does not distinguish between a missing key and an invalid key. Use a consistent 401 response with a generic message. For example, in your start/hooks.ts or within an Authenticator service, handle key validation as follows:

import { Exception } from '@adonisjs/core/build/standalone';

export class ApiKeyGuard {
  public async authenticate(key: string) {
    if (!key) {
      throw new Exception('Unauthorized', 401, 'E_UNAUTHORIZED');
    }
    const record = await Database.from('api_keys').where('key', key).first();
    if (!record) {
      throw new Exception('Unauthorized', 401, 'E_UNAUTHORIZED');
    }
    return record;
  }
}

This ensures that both missing and invalid keys result in the same status and body, preventing attackers from inferring validity through response differences.

Second, apply rate limiting to endpoints that accept API keys. AdonisJS supports rate limiting via the throttler middleware. Configure it in start/middleware.ts and attach it to routes that require key authentication:

import { HttpContextContract } from '@ioc:Adonis/Core/HttpContext';
import { middleware } from '@adonisjs/core';

const customThrottle = middleware.throttle({
  rate: 10, // 10 requests
  duration: 60, // per 60 seconds
  identifier: (ctx: HttpContextContract) => {
    return ctx.request.header('X-API-Key') || ctx.request.ip();
  },
});

export default customThrottle;

Attach this middleware to routes in routes.ts to limit brute force attempts per key or per IP:

Route.group(() => {
  Route.get('/secure', 'SecureController.show').middleware('customThrottle');
}).prefix('api/v1');

Third, consider rotating or expiring keys programmatically. Store metadata such as creation time and last used timestamp, and enforce policies that invalidate keys after suspicious activity. You can also introduce secondary checks, such as requiring a secondary token for sensitive operations, to reduce the impact of a compromised key.

Finally, integrate middleBrick into your workflow to scan your AdonisJS endpoints for authentication weaknesses and input validation issues. Use the CLI to test your API from the terminal:

middlebrick scan https://api.example.com

Or add the GitHub Action to your CI/CD pipeline to fail builds if the risk score drops below your chosen threshold, ensuring that authentication misconfigurations are caught before deployment.