Webhook Abuse in Adonisjs with Dynamodb

Webhook abuse in an AdonisJS application that uses DynamoDB as the primary event store can occur when untrusted external systems are allowed to create or trigger webhook deliveries without strict validation and authentication. AdonisJS handles HTTP requests through controllers and routes, and if a webhook endpoint is implemented as a public route, it may accept events from any source. When these events are written into DynamoDB for later processing, insufficient validation of the event origin, signature, and structure can lead to unauthorized task execution or data manipulation.

In this stack, a typical flow involves an external service posting a JSON payload to an AdonisJS route, which then stores the payload in a DynamoDB table using the AWS SDK for JavaScript v3. If the route does not verify the webhook secret or the integrity of the payload, an attacker can directly invoke the endpoint with crafted data. Because DynamoDB is often used as a durable queue or event log, the injected record may be picked up by a background worker or scheduled job and processed with elevated privileges, leading to issues such as BOLA (Broken Object Level Authorization) or unsafe consumption of untrusted data.

The risk is compounded when the webhook consumer trusts metadata such as headers or query parameters without cryptographic verification. For example, an endpoint that uses a timestamp and a signature header must validate the signature using a shared secret before writing to DynamoDB. Without this check, an attacker can replay requests or induce the server to process malicious payloads. Insecure DynamoDB configurations, such as over-permissive IAM policies attached to the application’s execution role, may further allow an attacker who compromises the webhook processing logic to read or modify unrelated records.

Because middleBrick tests unauthenticated attack surfaces and scans OpenAPI specs with full $ref resolution, it can identify missing authentication on webhook routes and gaps in authorization logic before malicious actors exploit them. The tool checks input validation and unsafe consumption patterns across the 12 security checks, including LLM/AI Security where relevant, and provides prioritized findings with severity and remediation guidance rather than attempting to fix the issues automatically.

To secure webhook handling in AdonisJS when using DynamoDB, validate and authenticate every incoming request before any data is written to the database. Use a verified webhook signature and enforce strict schema validation on the payload. The following examples demonstrate a hardened implementation using the AWS SDK for JavaScript v3 within an AdonisJS controller.

First, configure the DynamoDB client and define a strict Zod schema for expected webhook payloads. This ensures only well-formed data is stored or queued for processing:

import { DynamoDBClient } from '@aws-sdk/client-dynamodb';
import { DynamoDBDocumentClient, PutCommand } from '@aws-sdk/lib-dynamodb';
import { z } from '@adonisjs/zod';

const ddbClient = new DynamoDBClient({});
const ddb = DynamoDBDocumentClient.from(ddbClient);

const webhookSchema = z.object({
  event_id: z.string().uuid(),
  event_type: z.enum(['order.created', 'order.updated']),
  data: z.object({
    order_id: z.string().uuid(),
    amount: z.number().positive(),
    currency: z.string().length(3),
  }),
  timestamp: z.string().datetime(),
});

Next, implement the webhook route with HMAC verification using a shared secret stored in environment variables, and write the validated event to DynamoDB only after verification:

import { HttpContextContract } from '@ioc:Adonis/Core/HttpContext';
import crypto from 'crypto';

export default class WebhooksController {
  public async receive({ request, response }: HttpContextContract) {
    const payload = request.body();
    const signature = request.header('x-hub-signature-256');
    const secret = process.env.WEBHOOK_SECRET;

    if (!secret) {
      return response.badRequest({ error: 'server configuration' });
    }

    if (!signature || !signature.startsWith('sha256=')) {
      return response.unauthorized({ error: 'invalid signature header' });
    }

    const expected = 'sha256=' + crypto
      .createHmac('sha256', secret)
      .update(JSON.stringify(payload))
      .digest('hex');

    if (!crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(expected))) {
      return response.unauthorized({ error: 'invalid signature' });
    }

    const validated = webhookSchema.safeParse(payload);
    if (!validated.success) {
      return response.badRequest({ errors: validated.error.flatten().fieldErrors });
    }

    const params = {
      TableName: process.env.DYNAMODB_TABLE,
      Item: {
        event_id: validated.data.event_id,
        event_type: validated.data.event_type,
        data: validated.data.data,
        timestamp: new Date(validated.data.timestamp).toISOString(),
        processed: false,
      },
    };

    await ddb.send(new PutCommand(params));

    return response.ok({ status: 'queued' });
  }
}

In this flow, the signature is verified using crypto.timingSafeEqual to prevent timing attacks, and the payload is validated against a strict schema before being written to DynamoDB. The item includes a processed flag so that background workers can safely consume events without risking duplicate or unauthorized processing. Additionally, ensure the application’s IAM role follows least privilege, allowing only PutItem (or targeted write actions) on the specific DynamoDB table.

middleBrick can be used to verify that your webhook route enforces authentication and that the OpenAPI spec accurately reflects required security schemes. By scanning the endpoint, you can detect missing authentication, insufficient input validation, and unsafe consumption patterns. With the Pro plan, you can enable continuous monitoring so that any regression in webhook security is flagged promptly, and the GitHub Action can fail builds if the risk score drops below your chosen threshold.