Clickjacking in Chi with Jwt Tokens

Clickjacking is a client-side attack that tricks a user into interacting with a hidden or disguised UI element, often by loading a target site inside an invisible iframe. When JWT tokens are used for authentication in Chi, the presence of a valid token in a browser can make token leakage or session hijacking a consequence of a successful clickjack. Chi applications that embed third-party or same-origin pages in iframes without appropriate frame-ancestor controls may expose endpoints where a forged UI overlays sensitive actions or information. Because JWTs are typically stored in browser-accessible locations such as localStorage or sessionStorage, a page rendered under clickjacking conditions can expose tokens via DOM leaks or be used in social-engineered flows that trick users into performing actions that are authenticated automatically using the token.

In Chi, if an API response includes sensitive data and is rendered inside an iframe on a page controlled by an attacker, the token in local storage can be used to replay authenticated requests. For example, an app that uses JWTs for bearer authentication on routes like /api/transactions may inadvertently allow an embedded interface to perform state-changing operations when the user interacts with invisible controls. The risk is not in how JWTs are validated, but in how pages and iframes are composed: missing Content-Security-Policy frame-ancestors rules make it trivial to embed Chi pages in hostile contexts, and client-side code that reads the JWT and sends it to embedded third-party origins can leak the token through referrer headers or insecure cross-origin messaging. Even without direct token exfiltration, clickjacking can lead to unauthorized transactions or data views when the token grants access to high-privilege endpoints.

middleBrick scans detect whether pages are vulnerable to embedding and whether authentication mechanisms like JWTs are exposed in risky contexts. The scan checks for missing frame-ancestors directives, unsafe handling of authenticated routes inside iframes, and the presence of tokens in locations that can be reached by embedded content. These findings highlight how clickjacking and JWT handling intersect in Chi, guiding developers to isolate authenticated UI and enforce strict embedding rules.

To remediate clickjacking risks when using JWT tokens in Chi, apply defense-in-depth: enforce strict frame-ancestors policies, isolate authenticated routes from embedding, and avoid exposing tokens to untrusted origins. The following code examples show concrete configurations and patterns for Chi applications.

1) Enforce frame-ancestors via HTTP response headers

Set a strict Content-Security-Policy that limits which origins can embed your pages. In Chi, you can add middleware to inject headers on responses.

// chi middleware example: strict CSP frame-ancestors
import "net/http"
import "github.com/go-chi/chi/v5"
import "github.com/go-chi/chi/v5/middleware"

func secureHeaders(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        w.Header().Set("Content-Security-Policy", "frame-ancestors 'self'; report-uri /csp-report")
        next.ServeHTTP(w, r)
    })
}

func main() {
    r := chi.NewRouter()
    r.Use(middleware.RequestID)
    r.Use(secureHeaders)
    // your routes here
}

This policy ensures that only pages from the same origin can embed your Chi app, mitigating clickjacking that relies on iframes from external sites.

2) Isolate authenticated endpoints and avoid token leakage in embedded contexts

Do not allow pages that require JWT authentication to be framed. For sensitive routes, enforce same-origin framing or deny framing entirely. Additionally, avoid including JWTs in URLs or leaking them via the Referer header when navigating inside iframes.

// chi route that sets strict CSP for authenticated pages
r.Group(func(r chi.Router) {
    r.Use(jwtAuthMiddleware) // assume a middleware that validates JWTs
    r.Get("/dashboard", func(w http.ResponseWriter, r *http.Request) {
        w.Header().Set("Content-Security-Policy", "frame-ancestors 'self'")
        // render sensitive UI
    })
})

Consider using the X-Frame-Options header as an additional safeguard on legacy clients, but CSP frame-ancestors is the modern standard.

3) Secure JWT storage and client-side handling

On the client side, avoid storing JWTs in locations accessible to embedded third-party scripts. When your Chi app sets tokens, prefer httpOnly cookies for session-bound usage, or ensure that JavaScript-accessible storage is not readable from embedded frames. If you must use localStorage, isolate token usage to top-level origins and avoid passing tokens to cross-origin iframes.

// Example: setting a JWT in an httpOnly cookie via Chi middleware (server-side)
func jwtCookieMiddleware(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        // after validating the JWT, set it as an httpOnly cookie
        http.SetCookie(w, &http.Cookie{
            Name:     "auth_token",
            Value:    "",
            HttpOnly: true,
            Secure:   true,
            SameSite: http.SameSiteStrictMode,
            Path:     "/",
        })
        next.ServeHTTP(w, r)
    })
}

Use this alongside the frame-ancestors policy to reduce the attack surface for clickjacking involving JWTs. Validate the origin of requests on sensitive actions server-side, and consider anti-CSRF tokens for state-changing methods even when JWTs are used.