Information Disclosure in Echo Go

Information disclosure vulnerabilities in Echo Go applications typically emerge through improper handling of sensitive data in API responses and error messages. The most common pattern involves Echo Go's default error handling, which can inadvertently expose stack traces, database queries, or internal system details to unauthenticated users.

For example, when Echo Go's default HTTP error handler encounters an exception, it often returns detailed error messages containing file paths, line numbers, and even SQL queries. This becomes particularly problematic in development environments where debug mode is enabled. A typical vulnerable endpoint might look like this:

func (h *Handler) GetUserData(c echo.Context) error {
    userID := c.Param("id")
    user, err := h.repo.FindUserByID(userID)
    if err != nil {
        return err // Exposes database error details
    }
    return c.JSON(http.StatusOK, user)
}

The above code exposes database connection details and query structure when the repository layer returns an error. Echo Go's default behavior includes the full error chain in the HTTP response body, which can reveal:

• Database schema information
• Internal file system paths
• Third-party service endpoints
• Application version details
• Stack traces with function names

Another common Echo Go-specific disclosure pattern occurs with JSON marshaling. When struct fields are not properly tagged, Echo Go's JSON encoder may include sensitive fields like database IDs, internal timestamps, or even password hashes if they're accidentally included in the response struct:

type User struct {
    ID       string `json:"id"`
    Email    string `json:"email"`
    Password string `json:"password"` // Exposed if not tagged correctly
    Created  time.Time `json:"created"`
}

Echo Go's middleware system can also introduce information disclosure through verbose logging. When the Logger middleware is configured with debug level, it may log request bodies, headers, and response details that contain sensitive information like API keys, authentication tokens, or personal data.

Detecting information disclosure vulnerabilities in Echo Go applications requires both static analysis and runtime scanning. The most effective approach combines automated scanning with manual code review focused on Echo Go's specific patterns.

Using middleBrick's CLI tool, you can scan Echo Go endpoints for information disclosure with a single command:

middlebrick scan https://api.yourechoapp.com/user/123 --output json

middleBrick's scanner specifically targets Echo Go's common disclosure patterns, including:

• Default error responses that expose stack traces
• Unauthenticated endpoints returning sensitive user data
• Verbose logging middleware configurations
• Improper JSON struct tagging

The scanner runs 12 parallel security checks, with the Data Exposure check specifically looking for Echo Go's default behaviors. It tests endpoints with malformed inputs to trigger error conditions and analyzes the responses for sensitive information patterns.

For manual detection, examine your Echo Go application's error handling patterns. Look for:

// Vulnerable pattern - exposes full error details
return echo.NewHTTPError(http.StatusInternalServerError, err.Error())

// Better pattern - controlled error response
return echo.NewHTTPError(http.StatusInternalServerError, "An error occurred")

Also check for Echo Go's development mode configurations. When running with echo.New().Debug(true), the framework enables detailed error pages that can expose sensitive information to anyone who triggers an error.

middleBrick's OpenAPI analysis feature is particularly valuable for Echo Go applications since it can cross-reference your Swagger/OpenAPI spec with runtime findings. This helps identify endpoints that are documented to return sensitive data but may not have proper authentication controls.

Remediating information disclosure vulnerabilities in Echo Go requires a multi-layered approach that addresses both framework defaults and application-specific patterns. The first step is implementing proper error handling throughout your Echo Go application.

Replace Echo Go's default error handling with a custom error handler that sanitizes responses:

func customErrorHandler(err error, c echo.Context) {
    var code int
    var message string
    
    if he, ok := err.(*echo.HTTPError); ok {
        code = he.Code
        message = he.Message.(string)
    } else {
        code = http.StatusInternalServerError
        message = "An error occurred"
    }
    
    // Log the full error internally, but return sanitized response
    log.Printf("Error: %v", err)
    
    c.JSON(code, map[string]string{
        "error": message,
    })
}

e := echo.New()
e.HTTPErrorHandler = customErrorHandler

For JSON responses, use struct tags to control exactly what gets exposed:

type UserResponse struct {
    ID    string `json:"id"`
    Email string `json:"email"`
    // Exclude sensitive fields
    Password string `json:"-"`
    Created  time.Time `json:"-"`
}

func (h *Handler) GetUserData(c echo.Context) error {
    userID := c.Param("id")
    user, err := h.repo.FindUserByID(userID)
    if err != nil {
        return echo.NewHTTPError(http.StatusNotFound, "User not found")
    }
    
    response := UserResponse{
        ID:    user.ID,
        Email: user.Email,
    }
    
    return c.JSON(http.StatusOK, response)
}

Echo Go's middleware system provides additional protection. Configure the Logger middleware to exclude sensitive information:

e.Use(middleware.LoggerWithConfig(middleware.LoggerConfig{
    Format: "method=${method}, uri=${uri}, status=${status}\n",
    // Exclude request bodies and headers
    Output: os.Stdout,
}))

For development environments, create a separate configuration that enables detailed errors only for local development:

func setupEcho(debug bool) *echo.Echo {
    e := echo.New()
    
    if debug {
        e.Debug = true
        // Enable detailed errors only for localhost
        e.Use(middleware.CORSWithConfig(middleware.CORSConfig{
            AllowOrigins: []string{"http://localhost:3000"},
        }))
    } else {
        e.Debug = false
        e.HTTPErrorHandler = customErrorHandler
    }
    
    return e
}

Finally, implement input validation to prevent error conditions that might expose internal details. Echo Go's Validator middleware can help sanitize inputs before they reach your handlers:

e.Validator = &CustomValidator{validator: validate}

type CustomValidator struct {
    validator *validator.Validate
}

func (cv *CustomValidator) Validate(i interface{}) error {
    return cv.validator.Struct(i)
}