Broken Access Control in Axum with Cockroachdb

Broken Access Control occurs when an API exposes internal implementation details that allow unauthorized users to bypass intended authorization checks. In an Axum service backed by Cockroachdb, this commonly arises from incomplete server-side authorization logic combined with how application state and database rows are mapped.

Consider an endpoint that retrieves a user profile by ID. If the route parameter is used directly in a Cockroachdb query without verifying that the authenticated subject owns the requested resource, the unauthenticated or low-privilege actor can enumerate or manipulate IDs to access other users' data. Because Axum does not enforce authorization at the framework level, developers must explicitly embed scope and ownership checks before forming SQL statements. Missing or inconsistent checks in combination with dynamic query building against Cockroachdb can expose rows that should be invisible to the caller.

Another pattern that increases risk is constructing SQL with string interpolation instead of typed query parameters. For example, concatenating identifiers or using raw values from JSON payloads can bypass logical access controls if the surrounding Axum handlers do not validate tenant or team membership. Cockroachdb's SQL compatibility means that crafted requests can sometimes leverage secondary indexes or implicit ordering to infer existence of records, aiding enumeration attacks. In distributed setups, if connection pooling or session handling does not enforce tenant context consistently across handlers, a request intended for one organization may inadvertently query rows belonging to another, due to missing filter predicates on tenant_id or org_id columns.

Middleware that parses tokens and attaches identities is often reused across many routes. If the authorization layer only checks for authentication (presence of a token) and omits fine-grained role or permission checks, endpoints that interact with Cockroachdb can return data that should be restricted. Attackers may exploit this by making direct HTTP calls with valid tokens that have broader scopes than intended, especially when scopes are not validated against database-level constraints. The OWASP API Security Top 10 category for Broken Object Level Authorization (BOLA) / IDOR maps closely to these scenarios, where object references such as user IDs or resource IDs are exposed without proper authorization at the data layer.

SSRF and related infrastructure probing can indirectly assist in discovering Cockroachdb internals if the API exposes database errors or stack traces. Detailed error messages may reveal schema, table, or index names, which can be used to refine access control bypass attempts. Proper error handling in Axum, combined with strict validation of input parameters before building Cockroachdb queries, reduces the attack surface. Without these protections, the API effectively discloses access control logic through observable differences in response behavior or timing when accessing valid versus invalid resource identifiers.

Remediation centers on enforcing ownership and role checks before any Cockroachdb query, using parameterized SQL, and ensuring consistent tenant context. Below are concrete Axum handler examples demonstrating secure patterns.

First, define a typed query structure that binds identifiers via placeholders rather than string concatenation. This prevents accidental injection and ensures the planner uses safe execution paths.

use cockroachdb::Client; // hypothetical SDK client for illustration
use axum::extract::State;

struct AppState {
    db: Client,
    tenant_id: String,
}

async fn get_profile(
    State(state): State>,
    user_id: String,
    auth: AuthPrincipal, // your auth representation
) -> Result, (StatusCode, String)> {
    // Ensure the requesting subject owns the resource
    if auth.user_id != user_id && !auth.roles.contains(&"admin".to_string()) {
        return Err((StatusCode::FORBIDDEN, "access denied".into()));
    }

    let query = "SELECT id, display_name, email FROM profiles WHERE id = $1 AND tenant_id = $2";
    let row = state.db
        .query_one(query, &[&user_id, &state.tenant_id])
        .await
        .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;

    let profile = Profile {
        id: row.get(0),
        display_name: row.get(1),
        email: row.get(2),
    };
    Ok(Json(profile))
}

This handler validates ownership explicitly and uses positional parameters ($1, $2) for both the resource ID and the tenant context. The same approach extends to mutations. For example, updating a record should include the tenant and ownership predicate in the WHERE clause:

async fn update_email(
    State(state): State>,
    user_id: String,
    payload: Json,
    auth: AuthPrincipal,
) -> Result {
    if auth.user_id != user_id {
        return Err((StatusCode::FORBIDDEN, "cannot modify other users".into()));
    }

    let sql = "UPDATE profiles SET email = $1 WHERE id = $2 AND tenant_id = $3";
    let rows_affected = state.db
        .execute(sql, &[&payload.email, &user_id, &state.tenant_id])
        .await
        .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;

    if rows_affected == 0 {
        return Err((StatusCode::NOT_FOUND, "resource not found or access denied".into()));
    }
    Ok(StatusCode::NO_CONTENT)
}

For endpoints that accept multiple identifiers (such as organization-scoped resources), embed the tenant filter in every statement and avoid caching query plans that omit the tenant predicate. Using Axum extractors to normalize tenant resolution before reaching business logic helps keep the pattern consistent. In the Pro plan, continuous monitoring can detect anomalous queries that lack tenant filters, supporting compliance mappings to frameworks such as OWASP API Top 10 and SOC2.