Ssrf Server Side in Echo Go (Go)

Server-side request forgery (SSRF) in an Echo Go service occurs when user-controlled input is used to construct HTTP requests without adequate validation or network scoping. In Go, this often involves passing a URL from a query parameter or JSON body into an HTTP client such as http.DefaultClient or a custom http.Transport. Because Echo Go is a lightweight HTTP framework, developers may forward requests directly to user-supplied endpoints to implement proxy-like behavior, webhooks, or integration patterns. If the target URL is not strictly restricted, an attacker can direct the server to probe internal services, reach cloud metadata endpoints (e.g., 169.254.169.254), or bypass firewall rules that would otherwise protect internal resources.

The risk is amplified when the Go application runs in environments such as Kubernetes or cloud VMs, where metadata services expose credentials or instance metadata. An SSRF vulnerability can lead to internal service enumeration, access to instance profile credentials, or attacks against Redis, databases, and other protocols that accept TCP connections. Because Echo Go does not inherently restrict outbound targets, the developer must explicitly define a network allowlist, reject private IP ranges, and enforce timeouts and redirect policies. Without these controls, a seemingly harmless endpoint handler can become a pivot point for broader infrastructure compromise.

middleBrick can detect SSRF as part of its 12 parallel security checks. By submitting an API endpoint to the scanner, you receive a security risk score and findings that highlight unchecked request redirection, missing IP validation, and unsafe consumption patterns. These results map to real attack vectors such as CVE-associated techniques involving internal service access and metadata exfiltration, providing remediation guidance rather than attempting to fix the service automatically.

To remediate SSRF in Echo Go, validate and sanitize all user-supplied URLs before using them in HTTP requests. Use a strict allowlist of permitted hosts and ports, reject private and loopback IP ranges, and prefer relative paths or internal service identifiers instead of arbitrary external URLs. Configure the HTTP client with timeouts, disable automatic redirects, and avoid inheriting the server’s transport unless necessary. Below are concrete, safe patterns for Echo Go handlers.

Safe URL validation helper

import (
    "errors"
    "net"
    "net/http"
    "net/url"
    "strings"
)

func isPrivateIP(host string) bool {
    if ip := net.ParseIP(host); ip != nil {
        return ip.IsPrivate()
    }
    return false
}

func validateOutboundURL(raw string) error {
    parsed, err := url.ParseRequestURI(raw)
    if err != nil {
        return errors.New("invalid URL")
    }
    if parsed.Scheme != "http" && parsed.Scheme != "https" {
        return errors.New("unsupported scheme")
    }
    host := parsed.Hostname()
    if isPrivateIP(host) {
        return errors.New("private destination not allowed")
    }
    // Optional: allowlist specific domains
    allowed := map[string]bool{"api.example.com": true, "data.example.com": true}
    if !allowed[host] {
        return errors.New("destination not permitted")
    }
    return nil
}

Secure Echo Go handler with controlled HTTP client

import (
    "context"
    "net/http"
    "time"

    "github.com/labstack/echo/v4"
)

var (
    secureClient = &http.Client{
        Timeout: 10 * time.Second,
        Transport: &http.Transport{
            // restrict protocols and disable proxy
            Proxy: nil,
        },
    }
)

func safeProxyHandler(c echo.Context) error {
    target := c.QueryParam("url")
    if target == "" {
        return echo.NewHTTPError(http.StatusBadRequest, "url parameter required")
    }
    if err := validateOutboundURL(target); err != nil {
        return echo.NewHTTPError(http.StatusBadRequest, err.Error())
    }

    req, err := http.NewRequestWithContext(c.Request().Context(), http.MethodGet, target, nil)
    if err != nil {
        return echo.NewHTTPError(http.StatusBadRequest, "invalid request")
    }

    resp, err := secureClient.Do(req)
    if err != nil {
        return echo.NewHTTPError(http.StatusBadGateway, "failed to reach destination")
    }
    defer resp.Body.Close()

    // Forward status and limited safe headers only
    c.Response().WriteHeader(resp.StatusCode)
    // copy only safe headers if needed
    return nil
}

Using middleBrick CLI and GitHub Action

Integrate scanning into development workflows to catch SSRF and related issues early. From the terminal, run:

middlebrick scan https://api.example.com/webhook

In your CI pipeline, add the GitHub Action to fail builds if the risk score drops below your threshold:

uses: middleBrick/action@v1
with:
  url: ${{ secrets.TEST_API_URL }}
  threshold: C

For continuous monitoring, the Pro plan enables scheduled scans and alerts, while the MCP Server lets you scan APIs directly from your AI coding assistant within the IDE.