Auth Bypass in Strapi with Dynamodb

Strapi is a headless CMS that can use Amazon DynamoDB as a data store when configured with a custom connection. An Auth Bypass occurs when access controls are not consistently enforced between Strapi’s content API layer and the DynamoDB table. In such setups, misconfigured IAM policies, overly permissive resource-based policies, or unvalidated parameter usage can allow unauthenticated or low-privileged requests to invoke DynamoDB operations that should be restricted.

Consider a Strapi collection type Article mapped to a DynamoDB table named Articles. If the IAM role associated with the DynamoDB connection allows broad dynamodb:Query or dynamodb:Scan on the table and does not enforce ownership or tenant scoping, an authenticated attacker who compromises a low-privilege account might leverage Strapi’s GraphQL or REST endpoints to issue queries that return data belonging to other users. For example, a missing or incorrect filter on the userId attribute in Strapi’s resolver can result in DynamoDB queries that do not include the partition key constraint, effectively bypassing intended isolation.

Additionally, if Strapi’s DynamoDB connector uses the AWS SDK directly and constructs query parameters from user-supplied input without strict validation, an attacker might supply crafted key conditions that return unintended items. A common pattern is using a raw pk or sk value from request parameters to build a GetItem or Query request. Without validating that the requested identifier belongs to the requesting user’s scope, this can lead to IDOR-like access across DynamoDB items. This becomes an Auth Bypass when the underlying IAM policy permits the action irrespective of the authenticated identity, or when Strapi’s policies are not applied before the SDK call is made.

Another vector involves DynamoDB’s resource policies and cross-account permissions. If the table policy allows access from the Strapi application’s IAM role but does not restrict actions based on conditions such as aws:PrincipalArn or context derived from the API gateway, a misconfigured trust relationship might permit broader access than intended. Attackers can probe the unauthenticated attack surface—detected by tools like middleBrick—to identify endpoints where DynamoDB calls occur without proper pre-authentication checks. The interplay between Strapi’s role-based permissions and DynamoDB’s fine-grained IAM model requires precise alignment; otherwise, an attacker can exploit gaps to read or write data they should not access.

Remediation focuses on ensuring every DynamoDB operation is scoped to the authenticated user and validated before being passed to the AWS SDK. In Strapi, implement a service layer that enforces ownership checks and constructs safe query parameters. Never rely solely on Strapi’s default REST or GraphQL permissions if your data resides in DynamoDB; add explicit authorization before invoking the SDK.

Example: a Strapi service that performs a scoped query using the AWS SDK for DynamoDB. This code ensures the userId partition key is derived from the authenticated user and included in the key condition expression, preventing unauthorized cross-user queries.

const { DynamoDBClient, QueryCommand } = require("@aws-sdk/client-dynamodb");
const { marshall, unmarshall } = require("@aws-sdk/util-dynamodb");

const client = new DynamoDBClient({ region: "us-east-1" });

async function findArticlesByUser(userId) {
  if (!userId || typeof userId !== "string") {
    throw new Error("Invalid userId");
  }
  const params = {
    TableName: process.env.ARTICLES_TABLE_NAME,
    KeyConditionExpression: "pk = :pk",
    ExpressionAttributeValues: marshall({
      ":pk": { S: `USER#${userId}` },
    }),
  };

  const command = new QueryCommand(params);
  const response = await client.send(command);
  return response.Items.map((item) => unmarshall(item));
}

module.exports = { findArticlesByUser };

In your Strapi controller, call this service with the authenticated user’s ID from the request context, ensuring the DynamoDB request is constrained to that user’s partition key. Avoid passing raw user input into the KeyConditionExpression or constructing the partition key from unchecked parameters.

Additionally, enforce least-privilege IAM policies for the DynamoDB role used by Strapi. Instead of broad dynamodb:Query permissions, scope actions to specific table ARNs and conditionally require that the pk begins with a known prefix like USER#. Use conditions such as dynamodb:LeadingKeys to ensure queries are limited to the authenticated user’s partition key values. Regularly review table policies and access logs for anomalous patterns, noting findings through assessments available via middleBrick’s dashboard to track security posture over time.

Finally, apply input validation and type checks on any filters or sorting criteria derived from user input. Use allowlists for sort fields and ensure offset/limit parameters are integers within reasonable bounds. Combine these practices with Strapi’s built-in validation and the middleBrick CLI to scan endpoints for potential Auth Bypass indicators, integrating scans into CI/CD pipelines with the GitHub Action to fail builds when risky configurations are detected.