Ssrf in Buffalo with Cockroachdb

Server-Side Request Forgery (SSRF) in a Buffalo application that uses CockroachDB can emerge when user-supplied URLs are used to drive HTTP requests without adequate validation. Buffalo’s request handling and template rendering flow can inadvertently pass attacker-controlled input to HTTP clients, enabling the server to reach internal endpoints. Because CockroachDB is often deployed in clustered or multi-node environments with internal service discovery addresses, an SSRF vector can expose administrative HTTP interfaces, gossip ports, or internal SQL endpoints that are not exposed externally.

In a typical Buffalo app, an attacker might supply a URL like http://localhost:8080/admin or a CockroachDB node’s internal HTTP status endpoint (http://cockroach-node:8080/_status/vars) as a query parameter. If the app uses a generic HTTP client to fetch the provided URL and then parses the response (for example, to display remote metadata), the server can be forced to interact with internal services. Because CockroachDB’s admin UI and SQL proxy often bind to localhost or private network interfaces, SSRF can bypass network segregation and allow reconnaissance or data manipulation within the cluster.

When integrating with CockroachDB, applications sometimes use driver-level connection strings that embed hostnames or service names derived from external inputs (e.g., constructing a connection URL based on a user-supplied region or tenant identifier). If those inputs are not strictly validated, an SSRF flaw can lead to unauthorized connections to CockroachDB nodes, probing for misconfigured authentication or exposing cluster-internal routes. Even without direct SQL injection, SSRF can facilitate lateral movement by leveraging the database’s internal HTTP endpoints for status, metrics, or node information.

The risk is compounded when the Buffalo application runs in environments where CockroachDB is accessible via internal DNS names (e.g., cockroachdb-internal) or localhost ports. An SSRF payload that targets http://cockroachdb-internal:26257 may not reach the SQL port directly, but could interact with auxiliary HTTP services tied to the database nodes, enabling fingerprinting of cluster topology or triggering unintended side effects in poorly segmented deployments.

middleBrick can detect SSRF-related exposures by scanning the unauthenticated attack surface of a Buffalo app, including how it handles external URLs and whether responses reference internal network artifacts. While the scanner does not fix the issue, it provides remediation guidance aligned with OWASP API Top 10 and can map findings to compliance frameworks such as SOC2 and GDPR.

To mitigate SSRF in Buffalo applications that interact with CockroachDB, enforce strict allowlisting for any user-controlled input used in HTTP requests or database connection construction. Avoid concatenating user input directly into URLs or connection strings. Instead, use explicit configuration for database endpoints and validate all external targets before initiating requests.

Example: Unsafe URL fetching in Buffalo

import (
    "github.com/gobuffalo/buffalo"
    "net/http"
)

func unsafeFetch(c buffalo.Context) error {
    target := c.Param("url") // attacker-controlled
    resp, err := http.Get(target) // SSRF risk
    if err != nil {
        return c.Render(500, r.JSON(err))
    }
    defer resp.Body.Close()
    return c.Render(200, r.JSON(resp.Status))
}

Example: Safe URL allowlist in Buffalo

import (
    "github.com/gobuffalo/buffalo"
    "net/http"
    "strings"
)

var allowedHosts = map[string]bool{
    "api.example.com": true,
    "metadata.service": true,
}

func safeFetch(c buffalo.Context) error {
    target := c.Param("url")
    parsed, err := url.Parse(target)
    if err != nil {
        return c.Render(400, r.JSON(map[string]string{"error": "invalid URL"}))
    }
    if !allowedHosts[parsed.Host] {
        return c.Render(403, r.JSON(map[string]string{"error": "host not allowed"}))
    }
    resp, err := http.Get(target)
    if err != nil {
        return c.Render(500, r.JSON(err))
    }
    defer resp.Body.Close()
    return c.Render(200, r.JSON(resp.Status))
}

Example: Hardcoded CockroachDB connection string

import (
    "database/sql"
    _ "github.com/cockroachdb/cockroach-go/v2/crdb"
)

func connectToCockroach() (*sql.DB, error) {
    // Fixed, non-user-configurable connection string
    connStr := "postgresql://root@cockroachdb-internal:26257/defaultdb?sslmode=disable"
    db, err := sql.Open("cockroachdb", connStr)
    if err != nil {
        return nil, err
    }
    return db, db.Ping()
}

Example: Validating tenant input before constructing connection strings

import (
    "database/sql"
    "fmt"
    _ "github.com/cockroachdb/cockroach-go/v2/crdb"
)

var allowedTenants = map[string]string{
    "eu":  "cockroachdb-eu-internal:26257",
    "us":  "cockroachdb-us-internal:26257",
}

func tenantConnect(c buffalo.Context) error {
    tenant := c.Param("tenant")
    host, ok := allowedTenants[tenant]
    if !ok {
        return c.Render(400, r.JSON(map[string]string{"error": "invalid tenant"}))
    }
    connStr := fmt.Sprintf("postgresql://root@%s/defaultdb?sslmode=disable", host)
    db, err := sql.Open("cockroachdb", connStr)
    if err != nil {
        return err
    }
    return db.Ping()
}

Additionally, ensure that CockroachDB nodes are not exposed on localhost or internal-only interfaces that the Buffalo app can reach unless strictly required. Use network policies and service mesh controls to limit which components can initiate connections to database HTTP endpoints. Regularly review dependency versions and follow CockroachDB and Buffalo security advisories to address any transport-layer concerns.

middleBrick’s CLI can be used to scan a Buffalo endpoint with middlebrick scan <url>, returning security risk scores and findings related to SSRF and other checks. For teams integrating into development workflows, the GitHub Action can enforce security gates, while the MCP Server enables scanning from AI coding assistants within the IDE.