Clickjacking in Buffalo

Clickjacking attacks in Buffalo applications exploit the framework's HTML rendering pipeline to trick users into performing unintended actions. The vulnerability arises when Buffalo applications fail to implement proper frame-busting defenses, allowing malicious sites to embed Buffalo-rendered pages in invisible iframes.

In Buffalo, clickjacking typically occurs through two primary vectors:

• Form submission hijacking - Attackers embed a Buffalo form in a transparent iframe, overlaying it on top of what appears to be a legitimate page. When users believe they're clicking a benign button, they're actually submitting a Buffalo form.
• CSRF bypass attempts - While Buffalo's csrf.Generate middleware provides CSRF protection, clickjacking can still be used to bypass user awareness, making them perform actions they don't intend.

The Buffalo rendering pipeline processes templates through render.Renderer interfaces, which can inadvertently expose endpoints to clickjacking if not properly secured. This is particularly problematic for pages that handle sensitive operations like financial transactions, account modifications, or administrative functions.

A common Buffalo pattern that's vulnerable looks like this:

func UserSettingsHandler(c buffalo.Context) error {
    // No frame-busting headers
    return c.Render(200, r.HTML("user_settings.html"))
}

Without proper X-Frame-Options or Content-Security-Policy headers, this endpoint can be embedded in any external site, allowing attackers to overlay deceptive UI elements and capture user interactions.

Detecting clickjacking vulnerabilities in Buffalo applications requires examining both the application code and runtime behavior. Here's how to identify this issue:

Code-level detection involves scanning for endpoints that render HTML without frame-busting headers. Using middleBrick's black-box scanning capabilities, you can identify vulnerable endpoints by:

middlebrick scan https://your-buffalo-app.com/settings

The scan will test for clickjacking by attempting to embed the endpoint in an iframe and checking response headers. middleBrick specifically looks for:

• Missing X-Frame-Options header
• Missing Content-Security-Policy frame-ancestors directive
• Endpoints that return HTML content without frame protections

Runtime detection can be performed by examining HTTP response headers using curl:

curl -I https://your-buffalo-app.com/settings

Look for these critical headers that indicate proper clickjacking protection:

• X-Frame-Options: DENY or SAMEORIGIN
• Content-Security-Policy: frame-ancestors 'none' or 'self'

For Buffalo applications using the default github.com/gobuffalo/buffalo/render package, you can audit your route handlers to identify which endpoints render HTML without frame protections. Focus particularly on:

• Admin panels and dashboards
• Settings and configuration pages
• Payment and checkout flows
• Any form submission endpoints

Buffalo provides several approaches to implement clickjacking protection, ranging from global middleware to endpoint-specific controls. Here's how to secure your Buffalo application:

Global middleware approach - Apply frame-busting headers to all HTML responses:

import (
    "github.com/gobuffalo/buffalo/middleware"
    "github.com/gobuffalo/buffalo/render"
)

var r = render.New(render.Options{
    Tags:    render.XHTML,
    Headers: map[string]string{
        "X-Frame-Options": "DENY",
        "Content-Security-Policy": "frame-ancestors 'none'",
    },
})

func App() *buffalo.App {
    app := buffalo.New(buffalo.Options{
        Env:         ENV,
        SessionName: "_myapp_session",
    })
    
    // Apply to all HTML responses
    app.Use(func(next buffalo.Handler) buffalo.Handler {
        return func(c buffalo.Context) error {
            if c.Response().Header().Get("Content-Type") == "text/html" {
                c.Response().Header().Set("X-Frame-Options", "DENY")
                c.Response().Header().Set("Content-Security-Policy", "frame-ancestors 'none'")
            }
            return next(c)
        }
    })
    
    return app
}

Endpoint-specific protection - For more granular control, protect individual handlers:

func AdminPanelHandler(c buffalo.Context) error {
    c.Response().Header().Set("X-Frame-Options", "DENY")
    c.Response().Header().Set("Content-Security-Policy", "frame-ancestors 'none'")
    
    return c.Render(200, r.HTML("admin_panel.html"))
}

Conditional protection - Allow framing only from specific origins:

func ConditionalFrameHandler(c buffalo.Context) error {
    origin := c.Request().Header.Get("Origin")
    allowedOrigins := map[string]bool{
        "https://yourapp.com": true,
        "https://admin.yourapp.com": true,
    }
    
    if allowedOrigins[origin] {
        c.Response().Header().Set("X-Frame-Options", "ALLOW-FROM "+origin)
    } else {
        c.Response().Header().Set("X-Frame-Options", "DENY")
    }
    
    return c.Render(200, r.HTML("content.html"))
}

Testing your protection - Verify your implementation works:

func TestClickjackingProtection(t *testing.T) {
    app := App()
    
    // Test a protected endpoint
    req := httptest.NewRequest("GET", "/protected", nil)
    rr := httptest.NewRecorder()
    
    app.ServeHTTP(rr, req)
    
    if rr.Header().Get("X-Frame-Options") != "DENY" {
        t.Error("Missing X-Frame-Options header")
    }
    
    if !strings.Contains(rr.Header().Get("Content-Security-Policy"), "frame-ancestors") {
        t.Error("Missing CSP frame-ancestors directive")
    }
}