Insecure Direct Object Reference in Buffalo with Basic Auth

An Insecure Direct Object Reference (BOLA/IDOR) in a Buffalo application occurs when an endpoint uses user-supplied identifiers (e.g., /accounts/123) to access resources without verifying that the requesting identity is authorized for that specific object. When combined with HTTP Basic Authentication, the risk pattern changes: authentication is present, but authorization is missing or incomplete. Basic Auth provides a username/password pair that is typically validated once per request, after which the application may load a resource (like an invoice or profile) based solely on an ID in the URL, path parameter, or query string. If the application does not confirm that the authenticated user owns or is permitted to access that resource, the endpoint exposes a BOLA/IDOR.

Consider a Buffalo endpoint that retrieves a user’s bank statement by ID without ownership checks:

// In actions/transactions.go
func Show(c buffalo.Context) error {
    tx := &models.Transaction{}
    // ID taken directly from params, no ownership check
    if err := tx.Find(c.Param("transaction_id")); err != nil {
        return c.Render(500, r.JSON(err.Error()))
    }
    return c.Render(200, r.JSON(tx))
}

An authenticated attacker with Basic Auth credentials can iterate numeric IDs (or UUIDs) and access transactions belonging to other users. Because Basic Auth is often used in scripts or APIs, developers may assume the transport is sufficient, neglecting to enforce tenant or ownership checks. The scanner’s BOLA/IDOR checks will flag this when it detects authenticated-style endpoints (via Basic Auth headers) that access direct object references without verifying permissions, mapping the finding to OWASP API Top 10 A1: Broken Object Level Authorization and relevant compliance items such as SOC2 and GDPR.

Another common pattern is binding query or path parameters directly to models without scoping to the authenticated subject. For example, a handler that lists a user’s documents might do:

// In actions/documents.go
func List(c buffalo.Context) error {
    docs := &models.Documents{}
    // Missing: scope to current user; assumes params are safe
    if err := c.Params().Bind(docs); err != nil {
        return err
    }
    if err := tx.All(docs); err != nil {
        return err
    }
    return c.Render(200, r.JSON(docs))
}

Even with valid Basic Auth credentials, this code can return documents from other users if the query is not scoped (e.g., WHERE user_id = ?). The scanner’s OpenAPI/Swagger analysis will cross-reference spec definitions with runtime behavior; if the spec describes user-scoped paths but the implementation does not enforce scoping, the BOLA/IDOR is surfaced with severity and remediation guidance.

Remediation centers on ensuring that every object access is scoped to the authenticated identity. With Basic Auth, you typically have a current user available after authentication middleware validates credentials. Use that identity to constrain queries.

Corrected example for transaction retrieval with ownership check:

// In actions/transactions.go
func Show(c buffalo.Context) error {
    tx := &models.Transaction{}
    user := c.Value("current_user").(*models.User) // set by auth middleware
    // Scope by user_id, not just by supplied ID
    if err := tx.Where("user_id = ?", user.ID).Find(c.Param("transaction_id")); err != nil {
        return c.Render(404, r.JSON("not_found"))
    }
    return c.Render(200, r.JSON(tx))
}

For listing documents, scope the query to the authenticated user:

// In actions/documents.go
func List(c buffalo.Context) error {
    user := c.Value("current_user").(*models.User)
    docs := models.Documents{} // zero value used for WHERE clause
    // Build a scoped query; avoid binding raw user input as the WHERE target
    if err := tx.Where("user_id = ?", user.ID).All(&docs); err != nil {
        return err
    }
    return c.Render(200, r.JSON(docs))
}

When using Buffalo’s built-in authentication helpers, ensure the current user is populated before authorization checks. With Basic Auth, you might implement a before action that validates credentials and sets current_user:

// In actions/app.go or a before handler
func CurrentUser(c buffalo.Context) error {
    user, err := validateBasicAuth(c.Request()) // your own validation against DB
    if err != nil || user == nil {
        return c.Unauthorized()
    }
    c.Set("current_user", user)
    return nil
}

Also apply the principle of least privilege: avoid returning full objects or sensitive fields when not required. Use selective binding and response shaping. The Pro plan’s continuous monitoring can detect regressions where scoping is accidentally omitted, and the GitHub Action can fail builds if new endpoints lack ownership checks.