Privilege Escalation in Adonisjs with Dynamodb

AdonisJS is a Node.js web framework that encourages structured route handling, model-based interactions, and policy-based authorization. When integrating with Amazon DynamoDB as the persistence layer, privilege escalation risks arise if authorization checks are incomplete, overly permissive IAM policies are used, or if the application reflects user-controlled input into DynamoDB operations. A common pattern is to use a single DynamoDB client with broad permissions and perform row-level access checks in application code. If these checks are bypassed, missing, or incorrectly mapped to DynamoDB keys, an authenticated user can manipulate request parameters (e.g., :id) to access or modify records that belong to other users, effectively performing horizontal or vertical privilege escalation.

DynamoDB-specific factors that amplify risk include the lack of native row-level security, reliance on application logic for authorization, and the use of composite keys (partition key and sort key). For example, if an endpoint uses a predictable sort key pattern like USER#{userId}#profile and the controller uses req.user.id to construct the key but also accepts an id parameter for “self-service” views, an attacker can change :id to another user’s identifier and read or overwrite data if the IAM role attached to the AdonisJS process has broader write permissions (e.g., dynamodb:PutItem or dynamodb:UpdateItem without condition expressions). Insecure default configurations, such as using DynamoDB Local in development and inadvertently deploying with local credentials or overly permissive policies in production, further increase the attack surface. The framework’s flexibility around model definitions and hooks can also lead to implicit trust in request payloads that update sensitive attributes (isAdmin, role, permissions) if not explicitly guarded by policies.

Consider an AdonisJS controller that fetches a user profile by id without enforcing ownership or scope checks against the authenticated user. An attacker can iterate over plausible IDs or fuzz sort keys to enumerate profiles. Because DynamoDB responses differ based on permissions, error messages or timing differences can leak whether a record exists, aiding enumeration. If the same IAM credentials used by the app enable deletion or update across the table, an attacker who can tamper with the id parameter might issue destructive operations. This maps to OWASP API Top 10:2023 Broken Object Level Authorization (BOLA)/IDOR, which middleBrick tests as part of its 12 security checks. Proper mitigation requires combining framework-level policies with DynamoDB-aware authorization, strict IAM least privilege, and validation of all key components against the authenticated subject.

Remediation centers on ensuring every DynamoDB operation is scoped to the authenticated subject, using condition expressions to enforce ownership, and applying least-privilege IAM policies. Avoid constructing keys from unchecked input, and prefer parameterized queries with explicit key conditions.

1. Scope reads and writes to the authenticated user

Always derive partition and sort key components from the authenticated user’s identity rather than from request parameters. Use AdonisJS policies to encapsulate this logic.

// resources/Controllers/UserController.ts
import { HttpContextContract } from '@ioc:Adonis/Core/HttpContext'
import { DynamoDBClient, GetItemCommand } from '@aws-sdk/client-dynamodb'
import { marshall, unmarshall } from '@aws-sdk/util-dynamodb'

export default class ProfilesController {
  protected client = new DynamoDBClient({})

  public async show({ params, auth }: HttpContextContract) {
    const userId = auth.user?.id
    if (!userId) throw new Error('Unauthenticated')
    // Enforce ownership: do not use params.id directly
    const key = marshall({ pk: `USER#${userId}`, sk: 'PROFILE' })
    const cmd = new GetItemCommand({ TableName: process.env.DDB_TABLE!, Key: key })
    const resp = await this.client.send(cmd)
    if (!resp.Item) return null
    return unmarshall(resp.Item)
  }
}

2. Use condition expressions for updates to prevent tampering

When updating, include a condition that the partition/sort key matches the authenticated subject. This prevents privilege escalation via concurrent modification or malicious id substitution.

import { DynamoDBClient, UpdateItemCommand } from '@aws-sdk/client-dynamodb'
import { marshall, unmarshall } from '@aws-sdk/util-dynamodb'

export async function updateUserEmail(ctx: HttpContextContract) {
  const userId = ctx.auth.user?.id
  const { email } = ctx.request.body()
  if (!userId) throw new Error('Unauthenticated')

  const ddb = new DynamoDBClient({})
  const pk = `USER#${userId}`
  const cmd = new UpdateItemCommand({
    TableName: process.env.DDB_TABLE!,
    Key: marshall({ pk, sk: 'PROFILE' }),
    UpdateExpression: 'SET email = :val',
    ConditionExpression: 'attribute_exists(pk) AND pk = :pk',
    ExpressionAttributeValues: marshall({ ':val': email, ':pk': pk }),
    ReturnValues: 'UPDATED_NEW',
  })
  const resp = await ddb.send(cmd)
  return unmarshall(resp.Attributes || {})
}

3. Apply least-privilege IAM roles for the AdonisJS runtime

Ensure the IAM role or user associated with your AdonisJS application does not allow broader actions than needed. Use conditions like dynamodb:LeadingKeys to scope access to items where the partition key starts with a specific prefix (e.g., USER#). Avoid wildcards in Resource and Action for production workloads.

4. Validate and normalize keys in middleware

Add a request lifecycle hook or middleware that normalizes identifiers and rejects requests where the provided key does not match the authenticated subject.

// start/hooks.ts
import { HttpContextContract } from '@ioc:Adonis/Core/HttpContext'

export const enforceUserScope = async (ctx: HttpContextContract, next: () => Promise) => {
  const userId = ctx.auth.user?.id
  const targetId = ctx.params.id
  if (!userId || userId !== targetId) {
    ctx.response.status(403).send({ error: 'Forbidden: insufficient scope' })
    return
  }
  await next()
}

With these changes, privilege escalation through key manipulation is mitigated, and DynamoDB-specific risks are reduced. The checks align with middleBrick’s detections for BOLA/IDOR and BFLA/Privilege Escalation, and findings can be tracked in the dashboard or via the CLI to verify remediation.