Open Redirect in Buffalo with Cockroachdb

An open redirect in a Buffalo application using Cockroachdb typically occurs when user-controlled data is used to construct a redirect response without validation. Because Cockroachdb is often used to store tenant or campaign configuration, an attacker may be able to inject a malicious URL into a record that the application later reads and uses in redirect_to calls. If the application trusts the stored value and does not enforce an allowlist of safe domains, the redirect becomes open.

Buffalo’s typical pattern of binding query parameters or form fields to model fields, then saving to Cockroachdb, can inadvertently persist an untrusted URL. Later, when another request reads that URL from the database and calls redirect_to(url), the application performs an open redirect. This becomes especially risky when combined with social engineering: an attacker crafts a link like /offers?url=https://evil.example.com, the URL is stored in a Cockroachdb table, and subsequent users are redirected without warning.

The unauthenticated attack surface scanned by middleBrick includes endpoints that accept and store redirect targets. Even without authentication, an attacker can probe input points that eventually write to Cockroachdb. If the API or web handler reflects stored URLs into responses (e.g., in JSON fields or headers), middleBrick may surface this as a finding in the BOLA/IDOR or Input Validation checks, depending on how the data is exposed.

Because Cockroachdb is a distributed SQL database, it does not introduce new redirect mechanics, but it can serve as a persistence layer that keeps malicious payloads available across sessions. The vulnerability is not in Cockroachdb itself, but in how the Buffalo app reads, trusts, and uses stored values for navigation. middleBrick’s LLM/AI Security checks do not apply here; this is a classic web redirect issue mapped to OWASP API Top 10 A05:2023 (Security Misconfiguration) and A01:2023 (Broken Access Control) when access to the stored redirect target is inconsistent.

Remediation focuses on validating and normalizing any URL read from Cockroachdb before using it in a redirect. Use an allowlist of hostnames or enforce that the URL must be relative. Below are concrete, syntactically correct examples for a Buffalo application interacting with Cockroachdb via pq and database/sql.

1. Validate against an allowlist when reading redirect targets

When loading a redirect target from Cockroachdb, ensure the host is in an allowlist. This prevents storage of arbitrary external URLs from being used to redirect users.

package actions

import (
	"context"
	"net/url"
	"strings"

	"github.com/gobuffalo/buffalo"
	"github.com/gobuffalo/packr/v2"
	"github.com/jackc/pgx/v4/stdlib"
	"database/sql"
)

var allowedRedirectHosts = map[string]bool{
	"app.example.com": true,
	"static.example.com": true,
}

func safeRedirectTarget(ctx context.Context, db *sql.DB, id string) (string, error) {
	var target string
	row := db.QueryRowContext(ctx, "SELECT redirect_url FROM offers WHERE id = $1", id)
	if err := row.Scan(&target); err != nil {
		return "", err
	}
	parsed, err := url.Parse(target)
	if err != nil {
		return "", err
	}
	if !allowedRedirectHosts[parsed.Host] {
		return "", sql.ErrNoRows // treat as not allowed
	}
	return target, nil
}

func OffersShow(c buffalo.Context) error {
	id := c.Param("offer_id")
	db := c.Value("db").(*sql.DB)
	target, err := safeRedirectTarget(c.Request().Context(), db, id)
	if err != nil {
		c.Flash().Add("error", "invalid redirect target")
		return c.Redirect(400, rmsc.NotFound{})
	}
	return c.Redirect(302, target)
}

2. Enforce relative URLs for internal redirects

If redirects should only point within your app, store and use relative paths. This avoids host confusion entirely.

package actions

import (
	"context"

	"github.com/gobuffalo/buffalo"
	"github.com/jackc/pgx/v4/stdlib"
	"database/sql"
)

func InternalRedirect(c buffalo.Context) error {
	var path string
	db := c.Value("db").(*sql.DB)
	// Assume offers.route stores paths like "/offers/123"
	row := db.QueryRowContext(c.Request().Context(), "SELECT route FROM offers WHERE id = $1", c.Param("offer_id"))
	if err := row.Scan(&path); err != nil {
		return err
	}
	// Ensure path starts with / and does not contain host-like patterns
	if len(path) == 0 || path[0] != '/' {
		path = "/"
	}
	return c.Redirect(302, path)
}

3. Use middleBrick to validate your endpoints

Run a scan with the middleBrick CLI to surface any endpoints that accept redirect-like inputs and expose findings from the Input Validation and BOLA checks. The CLI can be used in scripts or CI/CD to ensure no open redirect patterns remain in staging before deploy.

middlebrick scan https://staging.example.com/api/offers