P2O-Vancouver-2021-ProxyShell-snippet-4.cs

private void OnAuthenticateRequest(object source, EventArgs args) { 
    HttpContext httpContext = HttpContext.Current; 
    if (httpContext.Request.IsAuthenticated) { 
        if (string.IsNullOrEmpty(httpContext.Request.Headers["X-CommonAccessToken"])) { 
            Uri url = httpContext.Request.Url; 
            Exception ex = null; 
            CommonAccessToken commonAccessToken = CommonAccessTokenFromUrl(httpContext. 
                User.Identity.ToString(), url, out ex); 
        } 
    } 
} 
 
private static CommonAccessToken CommonAccessTokenFromUrl(string user, Uri requestURI, out Exception ex) { 
    ex = null; 
    CommonAccessToken result = null; 
    string text = LiveIdBasicAuthModule.GetNameValueCollectionFromUri(requestURI).Get("X-Rps-CAT"); 
    if (!string.IsNullOrWhiteSpace(text)) { 
        try { 
            result = CommonAccessToken.Deserialize(Uri.UnescapeDataString(text)); 
        } catch (Exception ex2) { 
            // handle exception here 
        } 
    } 
    return result; 
}