Api Key Exposure in Echo Go with Basic Auth

When an Echo Go service uses HTTP Basic Authentication to guard an endpoint that returns an API key, the same credentials used for access control can inadvertently contribute to exposure if the transport or client handling is misconfigured. Basic Auth sends credentials as a base64-encoded string in the Authorization header, which is easily decoded without encryption. If the response containing the API key is served over HTTP instead of HTTPS, both the credentials and the key are traversing the network in clear text, making them trivially visible to on-path observers.

Even over HTTPS, combining Basic Auth with API key responses introduces a layered exposure scenario. The credentials authenticate the request, but the API key itself may be logged inadvertently by servers, proxies, or debugging tools that capture full request and response headers and bodies. In Echo Go, if route handlers write the Authorization header or the API key to logs, and those logs are centralized or retained longer than necessary, the combination of static credentials and long-lived API keys amplifies the impact of a single log exposure incident.

Another vector specific to this combination is mishandling of the Authorization header in client code. For example, an Echo Go client that reuses a single http.Client with a static Authorization header across multiple requests might inadvertently share credentials and keys across different contexts or services. If the API key is embedded in query parameters or response payloads and the Authorization header is also present, a misconfigured reverse proxy or load balancer might strip or rewrite headers inconsistently, causing the key to be returned in error messages or redirect flows that include the Basic Auth credentials.

middleBrick detects this risk pattern by scanning the unauthenticated attack surface and analyzing the OpenAPI specification alongside runtime behavior. For endpoints that return sensitive values such as API keys, it checks whether transport security is indicated, whether authentication mechanisms are consistent with best practices, and whether response examples or schemas expose secrets in ways that could be intercepted. The scan also flags endpoints where credentials and secrets coexist in headers or logs, helping teams understand how the combination of Basic Auth and key disclosure can create a chain of exposure.

Because middleBrick performs black-box scanning without agents or credentials, it can quickly highlight whether an Echo Go endpoint leaks an API key in responses while also relying on Basic Auth. Findings include guidance such as enforcing HTTPS, avoiding logging of secrets, and using short-lived tokens instead of long-lived API keys where feasible, reducing the window during which a compromised credential or key can be abused.

To remediate exposure when using Basic Auth in Echo Go, ensure all endpoints that return sensitive data such as API keys are served exclusively over HTTPS and that headers are handled defensively. Below are concrete, working examples that demonstrate secure handling of Basic Auth and safe response practices.

Enforce HTTPS and secure headers

Use middleware to redirect HTTP to HTTPS and to strip or avoid logging sensitive headers.

package main

import (
	"net/http"
	"strings"

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

func main() {
	e := echo.New()

	// Enforce HTTPS in production; reject insecure requests early.
	e.Pre(middleware.StripSlashes())
	e.Pre(middleware.SecureWithConfig(middleware.SecureConfig{
		XSSProtection:        "1; mode=block",
		ContentTypeNosniff:   "nosniff",
		XFrameOptions:        "DENY",
		SSLRedirect:          true,
		SSLHost:              "api.example.com",
		RequestHeadersSkips:  map[string]bool{"Healthz": true},
	}))

	// Custom middleware to avoid logging Authorization and API key headers.
	e.Use(middleware.RequestLoggerWithConfig(middleware.RequestLoggerConfig{
		LogURI:        true,
		LogStatus:     true,
		LogLatency:    true,
		LogErrorOnly:  false,
		Headers:       []string{"X-Request-ID"},
		Body:          "off",
		BeforeWrite: func(h middleware.WrapResponseWriter) {
			// Intentionally skip logging sensitive headers.
		},
	}))

	e.StartTLS(":8443", "server.crt", "server.key")
}

Safe Basic Auth handler that returns an API key only when appropriate

This handler validates credentials and returns an API key in the response body rather than exposing it in headers, minimizing leakage through logs or intermediaries.

package main

import (
	"encoding/base64"
	"net/http"
	"strings"

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

// Hardcoded example credentials; in production, use a secure store.
const validUser = "service"
const validPass = "s3cr3tP@ss"

func apiKeyHandler(c echo.Context) error {
	auth := c.Request().Header.Get("Authorization")
	if auth == "" {
		return echo.ErrUnauthorized
	}

	const prefix = "Basic "
	if !strings.HasPrefix(auth, prefix) {
		return echo.ErrUnauthorized
	}

	payload, err := base64.StdEncoding.DecodeString(auth[len(prefix):])
	if err != nil {
		return echo.ErrUnauthorized
	}

	pair := strings.SplitN(string(payload), ":", 2)
	if len(pair) != 2 || pair[0] != validUser || pair[1] != validPass {
		return echo.ErrUnauthorized
	}

	// Return the API key in the response body with clear content-type.
	// Avoid including the credentials or the API key in headers that may be logged.
	c.Response().Header().Set("Content-Type", "application/json")
	return c.JSON(http.StatusOK, map[string]string{
		"api_key": "ak_live_abc123def456",
	})
}

Client-side handling that avoids header reuse

Clients should set the Authorization header per request and avoid global clients that inadvertently share secrets across disparate calls.

package main

import (
	"net/http"
)

func callProtected() (*http.Response, error) {
	req, _ := http.NewRequest("GET", "https://api.example.com/v1/resource", nil)
	req.Header.Set("Authorization", "Basic c2VydmljZTpzZWNyZXRQYXNz")
	client := &http.Client{}
	return client.Do(req)
}

By combining HTTPS, careful header management, and limiting the scope of credentials and keys in logs and responses, the risk of Api Key Exposure in Echo Go services using Basic Auth is substantially reduced.