Insufficient Logging in Echo Go with Bearer Tokens

Insufficient logging in an Echo Go API that uses Bearer tokens can leave security events underrecorded, making it harder to detect and investigate incidents. When an API relies on Bearer tokens for authorization, each request carries a token that grants access to protected resources. If the server does not log key details—such as token identifiers, user associations, request paths, and outcomes—an attacker can probe the API and the operations team may lack an audit trail to trace misuse.

In the Echo Go ecosystem, this becomes a problem when handlers validate tokens but do not record enough context to reconstruct a timeline. For example, if a request with an invalid or revoked Bearer token reaches a sensitive route (e.g., user profile or admin endpoint) and the server only returns a generic 401 without logging the token fingerprint, requester IP, timestamp, and target route, the event may pass unnoticed. Similarly, successful authenticated requests that modify state (such as updating user settings or escalating privileges) might be logged at a coarse level, omitting which token was used and what specific changes occurred. This granularity gap weakens accountability and complicates incident response, especially when tokens are shared or accidentally exposed.

The risk is compounded when token validation logic is split across middleware and handlers, and logging is inconsistent between them. An attacker might exploit endpoints where logging is disabled or where sensitive data is masked inconsistently, leading to scenarios where token leakage through logs (such as accidentally printing the full Authorization header) occurs. MiddleBrick scans detect Insufficient Logging as one of the 12 parallel checks, highlighting missing context for authenticated operations and guiding teams to capture actionable security telemetry without exposing tokens themselves.

To address insufficient logging for Bearer tokens in Echo Go, enrich your middleware and handlers with structured logging that records non-sensitive, security-relevant context. Avoid logging the raw token; instead log a stable, non-reversible identifier derived from the token (such as a hash of the token or the subject claim), along with the HTTP method, path, status code, remote IP, and outcome. This preserves auditability while reducing the risk of token exposure in logs.

Below is a realistic, syntactically correct example of an Echo Go middleware that validates Bearer tokens and logs key events without exposing the token itself.

// main.go
package main

import (
    "crypto/sha256"
    "encoding/hex"
    "net/http"
    "strings"

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

// hashToken returns a non-reversible identifier for the token.
func hashToken(token string) string {
    h := sha256.New()
    h.Write([]byte(token))
    return hex.EncodeToString(h.Sum(nil))
}

func authMiddleware(next echo.HandlerFunc) echo.HandlerFunc {
    return func(c echo.Context) error {
        auth := c.Request().Header.Get("Authorization")
        const bearerPrefix = "Bearer "
        if !strings.HasPrefix(auth, bearerPrefix) {
            // Log unauthorized attempt without a token identifier
            c.Logger().Warn("auth: missing or malformed Authorization header")
            return c.NoContent(http.StatusUnauthorized)
        }
        token := strings.TrimPrefix(auth, bearerPrefix)
        tokenID := hashToken(token) // do not log raw token

        // Validate token with your backend (example stub):
        // valid, userID, err := validateBearer(token)
        valid := token == "exampleValidToken123" // replace with real validation
        if !valid {
            c.Logger().Warnf("auth: invalid token token_id=%s method=%s path=%s remote=%s", tokenID, c.Request().Method, c.Request().URL.Path, c.RealIP())
            return c.NoContent(http.StatusUnauthorized)
        }

        // Token is valid — log success with context
        c.Logger().Infof("auth: success token_id=%s method=%s path=%s remote=%s", tokenID, c.Request().Method, c.Request().URL.Path, c.RealIP())
        // Store user info in context for downstream handlers if needed
        c.Set("token_id", tokenID)
        return next(c)
    }
}

func adminHandler(c echo.Context) error {
    // Example of logging state-changing actions with token context
    tokenID, _ := c.Get("token_id").(string)
    // Perform admin action...
    c.Logger().Infof("action: admin_operation token_id=%s user=alice path=%s status=ok", tokenID, c.Request().URL.Path)
    return c.JSON(http.StatusOK, map[string]string{"status": "ok"})
}

func main() {
    e := echo.New()
    e.Use(middleware.Logger())
    e.Use(authMiddleware)
    e.GET("/admin", adminHandler)
    e.Logger.Fatal(e.Start(":8080"))
}

In this example, the middleware extracts the Bearer token, hashes it to produce a token_id, and uses that in log lines. The logs include the HTTP method, path, remote IP, and whether the outcome was success or failure. This approach ensures that repeated token usage can be traced without storing or exposing the raw token. For broader coverage, apply similar patterns to all routes that require authentication and ensure that logs are centralized and protected, following the guidance that middleware and handlers should record consistent, structured event data.