Broken Access Control in Rocket with Basic Auth

Broken Access Control occurs when API endpoints do not properly enforce authorization checks, allowing one user to access or modify resources belonging to another. When Basic Auth is used in a Rocket application without additional authorization logic, the vulnerability expands across three dimensions: Authentication, Authorization, and Data Exposure.

Authentication in Rocket with Basic Auth typically involves extracting a username and password from the Authorization header and validating credentials. While this confirms a user’s identity, it does not guarantee that the user is allowed to access a specific route or resource. If route handlers rely only on authentication and skip per-request authorization checks, the system conflates identity with permission. This is a common root cause of BOLA/IDOR and BFLA/Privilege Escalation findings that middleBrick flags in its 12 security checks.

In Rocket, handlers can be written to accept user claims from the request guard but then fail to verify that the requested resource (e.g., a document, record, or admin endpoint) belongs to that user or that the user holds the required role. For example, a handler might use a User guard to fetch the authenticated user, then directly load a Project by ID without checking ownership. An attacker who enumerates numeric IDs can iterate through other users’ projects, exploiting weak authorization logic. This becomes especially dangerous when endpoints expose sensitive data or allow mutations without verifying the requester’s rights.

Data Exposure is another critical dimension. Basic Auth sends credentials in an easily decoded header on every request. If responses include more data than necessary or lack proper filtering, attackers can harvest PII, API keys, or other sensitive information even when authentication succeeded. middleBrick’s Data Exposure and Property Authorization checks look for endpoints that return excessive fields or fail to enforce field-level authorization, which often coexist with Broken Access Control when Basic Auth is the only gate.

Real-world attack patterns mirror these risks. For instance, an unauthenticated or low-privilege attacker might use IDOR to change another user’s email or role by manipulating route parameters, especially when handlers trust client-supplied identifiers without re-checking ownership. OWASP API Top 10 A01:2023 (Broken Access Control) and related compliance frameworks highlight such scenarios. middleBrick scans detect these patterns by correlating authentication state with authorization checks across endpoints and flagging missing or inconsistent guards.

Remediation focuses on ensuring that authentication is followed by explicit authorization for every sensitive operation. Below are concrete, working examples of how to secure Rocket endpoints using Basic Auth while enforcing ownership and role checks.

First, define a user guard that extracts and validates credentials, then attach authorization logic inside handlers. Use Rocket’s RequestGuard to keep authentication separate from authorization.

use rocket::http::Status;
use rocket::request::{self, FromRequest, Request};
use rocket::{Outcome, RequestGuard};

#[derive(Debug)]
struct User {
    id: i32,
    username: String,
    role: String,
}

#[rocket::async_trait]
impl<'r> FromRequest<'r> for User {
    type Error = ();

    async fn from_request(req: &'r Request<'_>) -> request::Outcome {
        let auth = req.headers().get_one("authorization");
        let Some(auth) = auth else {
            return Outcome::Failure((Status::Unauthorized, ()));
        };
        if !auth.starts_with("Basic ") {
            return Outcome::Failure((Status::Unauthorized, ()));
        }
        let decoded = base64::decode(&auth[6..]).map_err(|_| (Status::Unauthorized, ()))?;
        let creds = String::from_utf8(decoded).map_err(|_| (Status::Unauthorized, ()))?;
        let parts: Vec<&str> = creds.split(':').collect();
        if parts.len() != 2 {
            return Outcome::Failure((Status::Unauthorized, ()));
        }
        // Replace with actual user lookup, e.g., via a database
        let user = match validate_user(parts[0], parts[1]) {
            Some(u) => u,
            None => return Outcome::Failure((Status::Unauthorized, ())),
        };
        Outcome::Success(user)
    }
}

fn validate_user(username: &str, password: &str) -> Option {
    // Example: in practice, verify credentials against a secure store
    if username == "alice" && password == "secret" {
        Some(User { id: 1, username: username.to_string(), role: "user".to_string() })
    } else if username == "admin" && password == "adminsecret" {
        Some(User { id: 2, username: username.to_string(), role: "admin".to_string() })
    } else {
        None
    }
}

Next, enforce ownership in each handler by comparing the authenticated user’s ID with the resource’s owner ID. Never rely on client-supplied IDs alone.

use rocket::serde::json::Json;
use rocket::State;

#[derive(serde::Deserialize)]
struct ProjectParams {
    project_id: i32,
}

#[get("/project/")]
async fn get_project(
    params: rocket::serde::json::Json,
    current_user: User,
    db: &State,
) -> Result, Status> {
    let project = web::block(move || {
        let conn = db.get().map_err(|_| ())?;
        projects::table
            .find(params.project_id)
            .first::(&conn)
            .optional()
            .map_err(|_| ())
    })
    .await
    .map_err(|_| Status::InternalServerError)?;

    let project = project.ok_or(Status::NotFound)?;
    if project.owner_id != current_user.id {
        return Err(Status::Forbidden);
    }
    Ok(Json(project))
}

For role-based access, create a guard or utility that checks permissions before allowing sensitive actions. This prevents privilege escalation when an attacker tries to invoke admin-only routes.

#[get("/admin/users")]
async fn list_users(current_user: User) -> Result {
    if current_user.role != "admin" {
        return Err(Status::Forbidden);
    }
    // Fetch and return user list
    Ok("{\"users\": []}".to_string())
}

Additionally, ensure responses do not leak data beyond what the authenticated and authorized user is entitled to see. Use serialization controls or field filtering to limit exposure. middleBrick’s Property Authorization and Data Exposure checks can help identify endpoints that return excessive or improperly filtered fields when Basic Auth is in use.