Bola Idor in Rocket with Dynamodb

Broken Object Level Authorization (BOLA) occurs when an API exposes a direct object reference (such as a DynamoDB key) without verifying that the requesting user is authorized to access that specific object. In a Rocket application using DynamoDB as the persistence layer, this typically happens when an endpoint accepts a user-supplied identifier (e.g., userId or recordId) and uses it to construct a DynamoDB request without confirming the requester’s permissions.

Consider a route like /users/:userId/profile. If the handler reads userId from the URL and issues a GetItem against DynamoDB using that value as the key, an attacker can change userId to another user’s ID and retrieve or modify profiles they should not see. Because DynamoDB is a low-level database, the authorization boundary must be enforced in application logic; DynamoDB itself does not enforce per-user ownership checks. Without such checks, the API surface includes the raw keys as object references, making BOLA straightforward to exploit.

Rocket’s routing and request handling amplify this when developers bind URL parameters directly to DynamoDB key attributes. For example, a GET handler that maps :id to PK and SK without validating that the authenticated subject owns that composite key enables horizontal privilege escalation. The DynamoDB request might include a condition expression that matches the provided key, but if the condition is missing or incorrectly scoped, the query returns data regardless of authorization context.

Common root causes include missing ownership checks (e.g., not comparing the authenticated user ID to the record’s ownerId attribute), over-permissive IAM policies that allow broad read/write access to table resources, and improper use of secondary indexes that expose additional lookup paths. Even if the API uses a service layer, if that layer trusts the client-supplied key and forwards it directly to DynamoDB, BOLA persists. A concrete DynamoDB request illustrating the risk might look like a GetItem where the key is derived entirely from user input:

const params = {
  TableName: process.env.USERS_TABLE,
  Key: {
    PK: { S: `USER#${userId}` },
    SK: { S: `PROFILE` }
  }
};

If userId is taken directly from the request, any authenticated or unauthenticated caller can enumerate IDs and access other users’ profiles. In Rocket applications that integrate DynamoDB, BOLA is often chained with other issues like missing rate limiting or weak authentication, increasing the potential impact.

Because middleBrick scans test the unauthenticated attack surface and include checks for Authorization and BOLA/IDOR, it can surface these misconfigurations by correlating endpoint behavior with DynamoDB access patterns. The scanner does not fix the flaw, but its findings include remediation guidance to help developers enforce proper ownership checks and scope requests correctly.

To remediate BOLA when using DynamoDB in Rocket, enforce ownership checks at the handler level and ensure every DynamoDB request includes a condition that ties the data access to the authenticated subject. Avoid using raw user input as the sole key; instead, derive composite keys that incorporate the user identifier and validate it against the request context.

One approach is to store a userId attribute on each item and verify it matches the authenticated subject before issuing any DynamoDB operation. For profile endpoints, construct the key using server-side values rather than trusting the client-supplied ID. Below is a safe pattern in Rocket that combines authentication extraction with a parameterized DynamoDB request:

use rocket::State;
use aws_sdk_dynamodb::Client;

#[rocket::get("/profile")]
async fn get_profile(
    client: &State,
    auth: AuthToken, // Assume this extracts and validates a subject identifier
) -> Result<Profile, ApiError> {
    let user_id = auth.user_id(); // Authenticated subject
    let table = std::env::var("USERS_TABLE").expect("USERS_TABLE must be set");

    let params = GetItemInputBuilder::default()
        .table_name(table)
        .key(
            hash_key("PK", format!("USER#{}", user_id)),
            range_key("SK", "PROFILE")
        )
        .build()
        .map_err(|_| ApiError::Internal)?;

    let output = client.get_item().set_input(Some(params)).send().await?;
    // Map output to Profile, ensuring no data is returned if the item does not exist
    Ok(Profile::try_from(output)?);
}

This pattern ensures the key is derived from the authenticated subject rather than from the request path. If you must accept an identifier in the route, validate it against the authenticated subject before building the DynamoDB key:

#[rocket::get("/users/<user_id>/settings")]
async fn get_settings(
    client: &State,
    user_id: &str,
    auth: AuthToken,
) -> Result<Settings, ApiError> {
    if auth.user_id() != user_id {
        return Err(ApiError::Forbidden);
    }
    let table = std::env::var("USERS_TABLE")?;
    let params = GetItemInputBuilder::default()
        .table_name(table)
        .key(
            hash_key("PK", format!("USER#{}", user_id)),
            range_key("SK", "SETTINGS")
        )
        .build()
        .map_err(|_| ApiError::Internal)?;

    let output = client.get_item().set_input(Some(params)).send().await?;
    Settings::try_from(output)
}

On the DynamoDB side, prefer condition expressions that assert ownership, especially when the item key itself does not encode the user context. For example, if items have an ownerId attribute, use a condition to ensure it matches the authenticated subject:

let params = UpdateItemInputBuilder::default()
    .table_name(table)
    .key(hash_key("PK", format!("USER#{}", user_id)))
    .condition_expression("attribute_exists(#owner) AND #owner = :owner")
    .expression_attribute_names({
        let mut m = HashMap::new();
        m.insert("#owner", "ownerId");
        m
    })
    .expression_attribute_values({
        let mut m = HashMap::new();
        m.insert(":owner", AttributeValue::S(auth.user_id()));
        m
    })
    .build()
    .map_err(|_| ApiError::Internal)?;

Additionally, apply least-privilege IAM policies so that Rocket service roles can only access items where the ownerId matches the authenticated subject, reducing the blast radius if a handler is misconfigured. The combination of server-side ownership checks, condition expressions, and scoped IAM permissions effectively neutralizes BOLA for DynamoDB-backed Rocket services.

middleBrick’s Pro plan supports continuous monitoring and CI/CD integration, which can help catch regressions that reintroduce BOLA after changes. Its scans include checks for Authorization and BOLA/IDOR and provide prioritized findings with remediation guidance, enabling teams to validate that DynamoDB access patterns remain properly constrained.