Ssrf Server Side in Buffalo with Cockroachdb

Server Side Request Forgery (SSRF) in a Buffalo application that uses CockroachDB can emerge from how HTTP clients are configured and how external data influences request targets. Because CockroachDB is often used as a distributed, cloud-native backend store, developers may build features that fetch or introspect external services (for migrations, schema discovery, or API integrations) and store connection or configuration details in CockroachDB. If an attacker can influence a URL stored in CockroachDB or supplied as input that is later used by a Buffalo HTTP client, the server can be forced to make arbitrary internal or external requests.

Buffalo applications written in Go typically use standard net/http clients or higher-level wrappers. When these clients follow user-controlled redirects or resolve hostnames dynamically, and the initial target metadata (e.g., host, port, path) resides in CockroachDB, SSRF surfaces. For example, a feature that allows on-demand sync to an arbitrary endpoint might store the endpoint in a database table, and later a Buffalo handler reads that entry and invokes http.Get without validation. An attacker who can write to that table (via another vector such as injection or compromised credentials) can effectively control the SSRF target, including internal CockroachDB node addresses, metadata services on cloud providers, or other services reachable from the application container.

The risk is compounded when the Buffalo app runs in environments where metadata services are reachable (e.g., cloud instance metadata at 169.254.169.254). A malicious entry in CockroachDB containing such URLs, or a crafted request that modifies in-memory configuration, can lead to data exfiltration via SSRF, including reading instance credentials or probing internal networks. Because CockroachDB stores configuration and runtime state, it can act as both the source of the attacker’s influence and the persistence layer for malicious entries, making detection harder.

middleBrick scans this attack surface by testing unauthenticated endpoints and inspecting how external input may flow into HTTP clients, including integrations with databases like CockroachDB. While the scanner does not modify data, it highlights findings such as SSRF and provides remediation guidance mapped to frameworks like OWASP API Top 10 and compliance regimes.

Remediation centers on strict input validation, allowlisting, and avoiding direct use of database-stored URLs in HTTP requests without rigorous checks. Below are concrete code examples for Buffalo that demonstrate safe patterns when working with CockroachDB.

• Use a strict allowlist for destinations: define permitted hosts and paths, and reject any user input that does not match exactly.
• Do not store arbitrary external URLs in CockroachDB without validation; if necessary, store only identifiers and resolve them server-side via a controlled mapping.
• Disable redirects and set timeouts on HTTP clients to limit SSRR impact and prevent SSRF escalation.

Example 1: Safe configuration fetch with allowlist

Assume a feature that selects a backend service identifier from CockroachDB. The application resolves the identifier to a predefined safe base URL, rather than using raw stored URLs.

-- Table schema (CockroachDB SQL)
CREATE TABLE service_configs (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    service_key TEXT NOT NULL UNIQUE,
    allowed_host TEXT NOT NULL -- restricted to known hosts
);

-- Insert allowed services (run once)
INSERT INTO service_configs (service_key, allowed_host) VALUES
('reporting', 'https://reports.internal.example.com'),
('metrics', 'https://metrics.internal.example.com');

// Go handler in Buffalo (safe pattern)
package actions

import (
    "context"
    "fmt"
    "net/http"

    "github.com/gobuffalo/buffalo"
    "github.com/jackc/pgx/v5"
)

func SyncReport(c buffalo.Context) error {
    // 1) Get validated service key from request (e.g., query param)
    serviceKey := c.Param("service")
    if serviceKey == "" {
        return c.Error(http.StatusBadRequest, fmt.Errorf("service parameter required"))
    }

    // 2) Fetch allowed host from CockroachDB using a prepared statement
    ctx := c.Request().Context()
    conn, err := pgx.Connect(ctx, "postgres://user:pass@cockroachdb-host:26257/defaultdb?sslmode=require")
    if err != nil {
        return c.Error(http.StatusInternalServerError, fmt.Errorf("db connection failed: %w", err))
    }
    defer conn.Close(ctx)

    var allowedHost string
    err = conn.QueryRow(ctx, "SELECT allowed_host FROM service_configs WHERE service_key = $1", serviceKey).Scan(&allowedHost)
    if err != nil {
        return c.Error(http.StatusNotFound, fmt.Errorf("service not configured: %w", err))
    }

    // 3) Use only the allowlisted host; do not concatenate user input into URLs
    url := allowedHost + "/v1/sync"
    client := &http.Client{
        Timeout: 10 * httpTimeout,
    }
    resp, err := client.Get(url)
    if err !=n nil {
        return c.Error(http.StatusBadGateway, fmt.Errorf("sync failed: %w", err))
    }
    defer resp.Body.Close()

    if resp.StatusCode != http.StatusOK {
        return c.Error(resp.StatusCode, fmt.Errorf("sync returned non-ok status: %d", resp.StatusCode))
    }

    return c.Render(200, r.JSON(map[string]string{"status": "ok"}))
}

Example 2: Avoid storing and using raw external URLs

Instead of persisting arbitrary external URLs in CockroachDB, store configuration keys and resolve them server-side. If you must store URLs, validate them against a strict schema before insertion.

-- Validation at insert time (CockroachDB)
INSERT INTO external_endpoints (name, url) VALUES
('legacy_export', 'https://export.internal.example.com/v2')
ON CONFLICT (name) DO NOTHING;

// Buffalo action with validation before using stored URL
package actions

import (
    "context"
    "net/http"
    "net/url"

    "github.com/gobuffalo/buffalo"
)

func ProxyHandler(c buffalo.Context) error {
    target := c.Param("target")
    storedURL, err := lookupValidEndpoint(target) // server-side lookup from CockroachDB
    if err != nil {
        return c.Error(http.StatusBadRequest, err)
    }

    parsed, err := url.Parse(storedURL)
    if err != nil || parsed.Scheme != "https" || !isAllowedHost(parsed.Host) {
        return c.Error(http.StatusBadRequest, fmt.Errorf("invalid endpoint"))
    }

    client := &http.Client{
        CheckRedirect: func(req *http.Request, via []*http.Request) error {
            return http.ErrUseLastResponse // disable redirects to prevent SSRF via open redirects
        },
    }
    resp, err := client.Get(parsed.String())
    if err != nil {
        return c.Error(http.StatusServiceUnavailable, err)
    }
    defer resp.Body.Close()

    // Stream or process response as needed
    return c.Render(200, r.JSON(map[string]string{"ok": "true"}))
}

These patterns ensure that CockroachDB does not become a source of untrusted data for SSRF while preserving functionality. middleBrick can verify these controls by scanning endpoints that interact with CockroachDB-stored configurations.