Auth Bypass in Adonisjs with Dynamodb

AdonisJS is a Node.js web framework that typically relies on session-based or JWT-based guards to enforce authentication. When integrating with DynamoDB as a user store, auth bypass can occur if the application fails to validate guard state on every request and instead relies on cached or loosely-scoped credentials. DynamoDB’s permission model uses IAM policies that may grant broader read/write access than intended for the user context. If the backend uses a shared DynamoDB client with elevated IAM credentials and does not scope requests per user, an attacker who bypasses the AdonisJS guard (for example, by tampering with session cookies or JWT tokens) can reuse the same credentials to access other users’ data.

In practice, this happens when routes relying on AdonisJS auth middleware do not enforce per-request identity checks against DynamoDB. For example, an endpoint might read a user identifier from the authenticated session but then query DynamoDB using a generic client that is not constrained to that user’s partition key. If the query key condition omits the user identifier or uses a non-validated input, an attacker can manipulate parameters to access other rows. A common pattern is fetching by ID without verifying that the ID belongs to the requesting user, which can lead to Insecure Direct Object Reference (IDOR) that effectively bypasses authentication controls.

Another vector involves DynamoDB’s conditional writes and permissions. If IAM policies attached to the application’s DynamoDB role allow PutItem or UpdateItem without explicit condition expressions that enforce ownership (e.g., username = :username), an attacker who manages to avoid AdonisJS auth checks can write or overwrite other users’ records. Real-world findings from scans show missing ownership checks in DynamoDB requests, where primary key values are derived from user input without cross-referencing the authenticated user’s ID. This aligns with BOLA/IDOR patterns mapped to OWASP API Top 10 and can be surfaced by middleBrick scans as authentication flaws combined with data exposure risks.

Remediation centers on ensuring that every DynamoDB operation is scoped to the authenticated user and that AdonisJS guards are validated before any database call. Use the AWS SDK for JavaScript v3 to construct narrowly-scoped IAM policies and enforce partition key constraints in queries. Below are concrete code examples for secure integration.

1. Scoped DynamoDB client with user context

Create a factory that returns a DynamoDB client configured with a session token and condition expression that ties operations to the current user. In AdonisJS, attach this to the container so each request gets a scoped client.

import { DynamoDBClient } from "@aws-sdk/client-dynamodb";
import { fromTemporaryCredentials } from "@aws-sdk/credential-providers";

// Example factory used within an AdonisJS service provider
export function createUserScopedClient(user) {
  return new DynamoDBClient({
    region: "us-east-1",
    credentials: fromTemporaryCredentials({
      params: {
        RoleArn: process.env.AWS_ROLE_ARN,
        Policy: JSON.stringify({
          Version: "2012-10-17",
          Statement: [
            {
              Effect: "Allow",
              Action: ["dynamodb:GetItem", "dynamodb:PutItem", "dynamodb:UpdateItem"],
              Resource: `arn:aws:dynamodb:${process.env.AWS_REGION}:*:table/${process.env.DYNAMODB_TABLE}`,
            },
            {
              Effect: "Allow",
              Action: ["dynamodb:Query"],
              Resource: `arn:aws:dynamodb:${process.env.AWS_REGION}:*:table/${process.env.DYNAMODB_TABLE}/index/*`,
              Condition: {
                ForAllValues:StringEquals: {
                  "dynamodb:LeadingKeys": ["${user.id}"]
                }
              }
            }
          ]
        })
      }
    })
  });
}

2. Safe query with ownership check in a controller

Always derive the key condition from the authenticated user identity, not from untrusted input alone.

import { DynamoDBClient, QueryCommand } from "@aws-sdk/client-dynamodb";
import { unmarshall } from "@aws-sdk/util-dynamodb";

export async function getUserProfile(userId) {
  const client = new DynamoDBClient({ region: "us-east-1" });
  const command = new QueryCommand({
    TableName: process.env.DYNAMODB_TABLE,
    IndexName: "GSI_EMAIL",
    KeyConditionExpression: "userId = :uid",
    ExpressionAttributeValues: {
      ":uid": { S: userId }
    }
  });

  const response = await client.send(command);
  return response.Items.map(unmarshall);
}

// In an AdonisJS controller
Route.get("/profile", async ({ auth }) => {
  const user = await auth.getUser();
  const profiles = await getUserProfile(user.id);
  return profiles;
});

3. Conditional writes to enforce ownership

Use ConditionExpression to ensure updates only succeed when the item belongs to the authenticated user.

import { DynamoDBClient, UpdateItemCommand } from "@aws-sdk/client-dynamodb";

export async function updateUserSettings(userId, settings) {
  const client = new DynamoDBClient({ region: "us-east-1" });
  const command = new UpdateItemCommand({
    TableName: process.env.DYNAMODB_TABLE,
    Key: {
      userId: { S: userId }
    },
    UpdateExpression: "set #prefs = :prefs",
    ConditionExpression: "attribute_exists(userId) AND userId = :uid",
    ExpressionAttributeNames: {
      "#prefs": "preferences"
    },
    ExpressionAttributeValues: {
      ":prefs": { S: JSON.stringify(settings) },
      ":uid": { S: userId }
    }
  });
  await client.send(command);
}

4. Middleware to enforce authentication before DynamoDB access

Ensure AdonisJS guards are invoked and attach user identity to the request context for downstream use.

import { middleware } from "@adonisjs/core";

export const ensureAuthenticated = middleware(async (ctx, next) => {
  const { auth } = ctx;
  const user = await auth.authenticate();
  ctx.authUser = user; // pass to services
  await next();
});

Combine these practices to eliminate auth bypass: always scope queries to the authenticated user’s partition key, apply condition expressions, and validate guards before issuing DynamoDB requests. This reduces IDOR and privilege escalation risks and aligns findings remediation guidance provided by security scans.