Broken Access Control in Echo Go with Cockroachdb

Broken Access Control occurs when an API does not properly enforce permissions between different users or roles, allowing one user to act on another user's resources. When building services in Echo Go that use Cockroachdb as the backing store, this risk is amplified if authorization checks are implemented at the application layer only and not validated server-side by the database.

Consider an endpoint like /users/{userID} built with Echo Go and backed by Cockroachdb. If the route handler retrieves the requested userID from the URL, constructs a Cockroachdb query using string concatenation or simple placeholders, and omits a server-side check that the authenticated user owns or is allowed to view that row, an authenticated attacker can change the userID path parameter to access another user’s data. Cockroachdb will return the row if the SQL is permissive (for example, a broad SELECT without row-level security or a predicate that trusts the caller), and Echo Go will return the data without escalation or denial.

An insecure implementation might look like this:

// Insecure Echo Go handler — vulnerable to BOLA/IDOR
func getUser(c echo.Context) error {
    userID := c.Param("userID")
    var email string
    // WARNING: directly interpolating user input into SQL
    sql := fmt.Sprintf("SELECT email FROM users WHERE id = %s", userID)
    row := db.QueryRow(sql)
    if err := row.Scan(&email); err != nil {
        return c.String(http.StatusInternalServerError, "error")
    }
    return c.JSON(http.StatusOK, map[string]string{"email": email})
}

In this scenario, there is no ownership or role check; the SQL trusts the caller-supplied userID. Because Cockroachdb executes the statement as written, an attacker can enumerate or exfiltrate other users’ emails. Additionally, if the API key or JWT claims are not validated on each request within Echo Go, or if the token’s scopes are not mapped to precise SQL predicates, the attack surface grows. This is a classic Broken Access Control issue (OWASP API Top 10: Broken Object Level Authorization), where the server-side authorization boundary is missing or misaligned between the application and Cockroachdb.

Another common pattern is using Cockroachdb’s secondary indexes without verifying that the authenticated user is allowed to filter by the chosen index key. For example, an endpoint that lists user-owned resources might append a tenant ID to the WHERE clause only after reading a header, but if the header is optional or spoofed, the query may return data outside the intended tenant. Because Cockroachdb efficiently serves indexed queries, missing authorization checks result in fast, data-exfiltrating endpoints.

To map this to middleBrick’s checks, the scanner tests unauthenticated and authenticated scenarios to detect missing authorization at both the API and data layers, flagging findings such as BOLA/IDOR and Property Authorization with relevant severity and remediation guidance.

Remediation focuses on enforcing server-side authorization for every data access, using parameterized SQL, and validating tenant or ownership context on each request. In Echo Go, this means extracting the authenticated subject from verified claims and using it as a strict filter in Cockroachdb queries.

First, always use placeholders to avoid SQL injection and ensure the query plan is stable. Second, include the authenticated user’s ID or tenant ID directly in the WHERE clause so Cockroachdb enforces the boundary:

// Secure Echo Go handler with Cockroachdb
func getUser(c echo.Context) error {
    // Assume auth middleware has set user claims in context
    claims := c.Get("claims").(*jwtclaims)
    requestedUserID := c.Param("userID")

    var email string
    // Use a parameterized query and restrict by authenticated subject
    sql := "SELECT email FROM users WHERE id = $1 AND owner_id = $2"
    row := db.QueryRow(sql, requestedUserID, claims.UserID)
    if err := row.Scan(&email); err != nil {
        if errors.Is(err, sql.ErrNoRows) {
            return c.String(http.StatusForbidden, "access denied")
        }
        return c.String(http.StatusInternalServerError, "error")
    }
    return c.JSON(http.StatusOK, map[string]string{"email": email})
}

In this secure pattern, owner_id is a column in Cockroachdb that stores the user ID that owns the row. The query uses two placeholders ($1, $2) to bind the requested user ID and the authenticated user ID. Cockroachdb will only return the row if both conditions match, enforcing BOLA protection at the data plane.

For tenant-based data isolation, apply the same principle:

// Multi-tenant secure handler
func listDocuments(c echo.Context) error {
    tenantID := c.Get("tenantID").(string)
    var rows []Document
    sql := "SELECT id, title FROM documents WHERE tenant_id = $1"
    if err := db.Select(&rows, sql, tenantID); err != nil {
        return c.String(http.StatusInternalServerError, "error")
    }
    return c.JSON(http.StatusOK, rows)
}

Here, the tenant ID extracted from a verified source (e.g., JWT or SSO session) is the sole filter in the WHERE clause. Even if the API allows listing documents, Cockroachdb ensures that no document from another tenant is returned. This pattern should be applied to every endpoint that accesses Cockroachdb rows.

Additionally, prefer using an ORM or query builder that enforces parameterization and avoids string interpolation. If you must construct dynamic queries, validate and sanitize inputs rigorously and always include ownership or tenant predicates. Combine these database-side controls with application-level checks and rate limiting to reduce abuse, but remember that database-enforced filters are the authoritative boundary.

These fixes align with middleBrick’s findings for BOLA/IDOR and Property Authorization. The scanner can verify that authenticated requests cannot access other users’ or tenants’ data by probing endpoints with varied subjects and inspecting responses for unauthorized data leakage.