FormsAuthentication.Signout () protokolliert den Benutzer nicht

https://stackoverflow.com/questions/412300

03-07-2019
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Frage

Ich habe meinen Kopf etwas zu lange dagegen geschlagen. Wie kann ich einen Benutzer daran hindern, die Seiten einer Website zu stöbern, nachdem er mithilfe von FormsAuthentication.Signout angemeldet wurde? Ich würde es erwarten, dass dies tut:

FormsAuthentication.SignOut();
Session.Abandon();
FormsAuthentication.RedirectToLoginPage();

Aber es tut es nicht. Wenn ich eine URL direkt einmachte, kann ich trotzdem zur Seite stöbern. Ich habe seit einiger Zeit keine Sicherheit mehr verwendet, also vergesse ich, warum das nicht funktioniert.

Lösung

Benutzer können weiterhin Ihre Website durchsuchen, da Cookies beim Anruf nicht gelöscht werden FormsAuthentication.SignOut() Und sie sind bei jeder neuen Anfrage authentifiziert. In MS wird die Dokumentation besagt, dass Cookie gelöscht wird, aber nicht, Fehler? Es ist genau das gleiche mit Session.Abandon(), Cookie ist immer noch da.

Sie sollten Ihren Code darauf ändern:

FormsAuthentication.SignOut();
Session.Abandon();

// clear authentication cookie
HttpCookie cookie1 = new HttpCookie(FormsAuthentication.FormsCookieName, "");
cookie1.Expires = DateTime.Now.AddYears(-1);
Response.Cookies.Add(cookie1);

// clear session cookie (not necessary for your current problem but i would recommend you do it anyway)
SessionStateSection sessionStateSection = (SessionStateSection)WebConfigurationManager.GetSection("system.web/sessionState");
HttpCookie cookie2 = new HttpCookie(sessionStateSection.CookieName, "");
cookie2.Expires = DateTime.Now.AddYears(-1);
Response.Cookies.Add(cookie2);

FormsAuthentication.RedirectToLoginPage();

HttpCookie ist in dem System.Web Namespace. MSDN -Referenz.

Andere Tipps

Klingt für mich so, als hätten Sie Ihren Abschnitt "Web.Config" nicht ordnungsgemäß eingerichtet. Ein Beispiel finden Sie unten.

<authentication mode="Forms">
  <forms name="MyCookie" loginUrl="Login.aspx" protection="All" timeout="90" slidingExpiration="true"></forms>
</authentication>
<authorization>
  <deny users="?" />
</authorization>

Die Verwendung von zwei der oben genannten Beiträge von x64igor und Phil Haselden lösten dies:

1. x64igor gab das Beispiel, um das Abmeldung durchzuführen:

Sie müssen zuerst müssen Löschen Sie den Authentifizierungs -Cookie und das Session Cookie Durch das Zurückgeben leerer Cookies in der Antwort auf das Abmelden.

public ActionResult LogOff()
{
    FormsAuthentication.SignOut();
    Session.Clear();  // This may not be needed -- but can't hurt
    Session.Abandon();

    // Clear authentication cookie
    HttpCookie rFormsCookie = new HttpCookie( FormsAuthentication.FormsCookieName, "" );
    rFormsCookie.Expires = DateTime.Now.AddYears( -1 );
    Response.Cookies.Add( rFormsCookie );

    // Clear session cookie 
    HttpCookie rSessionCookie = new HttpCookie( "ASP.NET_SessionId", "" );
    rSessionCookie.Expires = DateTime.Now.AddYears( -1 );
    Response.Cookies.Add( rSessionCookie );

2. Phil Haselden gab das obige Beispiel, wie das Zwischenspeichern nach dem Abmelden verhindern kann:

Du musst Der Cache auf der Clientseite über die Antwort ungültig machen.

    // Invalidate the Cache on the Client Side
    Response.Cache.SetCacheability( HttpCacheability.NoCache );
    Response.Cache.SetNoStore();

    // Redirect to the Home Page (that should be intercepted and redirected to the Login Page first)
    return RedirectToAction( "Index", "Home" ); 
}

Der Schlüssel hier ist, dass Sie sagen: "Wenn ich eine URL direkt eingeben ...".

Standardmäßig unter Formularen Authentifizierung richtungsseiten für den Benutzer. Wenn Sie also eine URL direkt aus dem Dropdown -Bereich der Browser -Adresskästchen auswählen oder eingeben, können Sie die Seite vom Browser -Cache eingeben und niemals zum Server zurückkehren, um die Authentifizierung/Autorisierung zu überprüfen. Die Lösung hierfür besteht darin, das clientseitige Caching im Ereignis page_load jeder Seite oder in der Onload () Ihrer Basisseite zu verhindern:

Response.Cache.SetCacheability(HttpCacheability.NoCache);

Sie könnten auch gerne anrufen:

Response.Cache.SetNoStore();

I've struggled with this before too.

Here's an analogy for what seems to be going on... A new visitor, Joe, comes to the site and logs in via the login page using FormsAuthentication. ASP.NET generates a new identity for Joe, and gives him a cookie. That cookie is like the key to the house, and as long as Joe returns with that key, he can open the lock. Each visitor is given a new key and a new lock to use.

When FormsAuthentication.SignOut() is called, the system tells Joe to lose the key. Normally, this works, since Joe no longer has the key, he cannot get in.

However, if Joe ever comes back, and does have that lost key, he is let back in!

From what I can tell, there is no way to tell ASP.NET to change the lock on the door!

The way I can live with this is to remember Joe's name in a Session variable. When he logs out, I abandon the Session so I don't have his name anymore. Later, to check if he is allowed in, I simply compare his Identity.Name to what the current session has, and if they don't match, he is not a valid visitor.

In short, for a web site, do NOT rely on User.Identity.IsAuthenticated without also checking your Session variables!

This works for me

public virtual ActionResult LogOff()
    {
        FormsAuthentication.SignOut();
        foreach (var cookie in Request.Cookies.AllKeys)
        {
            Request.Cookies.Remove(cookie);
        }
        foreach (var cookie in Response.Cookies.AllKeys)
        {
            Response.Cookies.Remove(cookie);
        }
        return RedirectToAction(MVC.Home.Index());
    }

After lots of search finally this worked for me . I hope it helps.

public ActionResult LogOff()
{
    AuthenticationManager.SignOut();
    HttpContext.User = new GenericPrincipal(new GenericIdentity(string.Empty), null);
    return RedirectToAction("Index", "Home");
}

<li class="page-scroll">@Html.ActionLink("Log off", "LogOff", "Account")</li>

The code you posted looks like it should correctly remove the forms authentication token, so it is possible that the folders/pages in question are not actually protected.

Have you confirmed that the pages cannot be accessed before a login has occured?

Can you post the web.config settings and login code that you are using?

I have been writing a base class for all of my Pages and I came to the same issue. I had code like the following and It didn't work. By tracing, control passes from RedirectToLoginPage() statement to the next line without to be redirected.

if (_requiresAuthentication)
{
    if (!User.Identity.IsAuthenticated)
        FormsAuthentication.RedirectToLoginPage();

    // check authorization for restricted pages only
    if (_isRestrictedPage) AuthorizePageAndButtons();
}

I found out that there are two solutions. Either to modify FormsAuthentication.RedirectToLoginPage(); to be

if (!User.Identity.IsAuthenticated)
    Response.Redirect(FormsAuthentication.LoginUrl);

OR to modify the web.config by adding

<authorization>
  <deny users="?" />
</authorization>

In the second case, while tracing, control didn't reach the requested page. It has been redirected immediately to the login url before hitting the break point. Hence, The SignOut() method isn't the issue, the redirect method is the one.

I hope that may help someone

Regards

I just tried some of the suggestions here and while I was able to use the browser back button, when I clicked on a menu selection the [Authorize] token for that [ActionResult] sent me right back to the login screen.

Here is my logout code:

        FormsAuthentication.SignOut();
        Response.Cookies.Remove(FormsAuthentication.FormsCookieName);
        Response.Cache.SetExpires(DateTime.Now.AddSeconds(-1));
        HttpCookie cookie = HttpContext.Request.Cookies[FormsAuthentication.FormsCookieName];
        if (cookie != null)
        {
            cookie.Expires = DateTime.Now.AddDays(-1);
            Response.Cookies.Add(cookie);
        }

Although the back function on the browser took me back and displayed the secured menu (I am still working on that) I was not able to do anything that was secured in the app.

Hope this helps

I've tried most answers in this thread, no luck. Ended up with this:

protected void btnLogout_Click(object sender, EventArgs e)
{
    FormsAuthentication.Initialize();
    var fat = new FormsAuthenticationTicket(1, "", DateTime.Now, DateTime.Now.AddMinutes(-30), false, string.Empty, FormsAuthentication.FormsCookiePath);
    Response.Cookies.Add(new HttpCookie(FormsAuthentication.FormsCookieName, FormsAuthentication.Encrypt(fat)));
    FormsAuthentication.RedirectToLoginPage();
}

Found it here: http://forums.asp.net/t/1306526.aspx/1

This Answer is technically identical to Khosro.Pakmanesh. I'm posting it to clarify how his answer differs from other answers on this thread, and in which use case it can be used.

In general to clear a user-session, doing

HttpContext.Session.Abandon();
FormsAuthentication.SignOut();

will effectively log out the user. However, if in the same Request you need to check Request.isAuthenticated (as may often happen in an Authorization Filter, for example), then you will find that

Request.isAuthenticated == true

even _after you did HttpContext.Session.Abandon() and FormsAuthentication.SignOut().

The only thing that worked was doing

AuthenticationManager.SignOut();
HttpContext.User = new GenericPrincipal(new GenericIdentity(string.Empty), null);

That effectively sets Request.isAuthenticated = false.

This started happening to me when I set the authentication > forms > Path property in Web.config. Removing that fixed the problem, and a simple FormsAuthentication.SignOut(); again removed the cookie.

It could be that you are logging in from one subdomain (sub1.domain.com) and then trying to logout from a different subdomain (www.domain.com).

I just had the same problem, where SignOut() seemingly failed to properly remove the ticket. But only in a specific case, where some other logic caused a redirect. After I removed this second redirect (replaced it with an error message), the problem went away.

The problem must have been that the page redirected at the wrong time, hence not triggering authentication.

I am having a similar issue now and I believe the problem in my case as well as the original poster is because of the redirect. By default a Response.Redirect causes an exception which immediately bubbles up until it is caught and the redirect is immediately executed, I am guessing that this is preventing the modified cookie collection from being passed down to the client. If you modify your code to use:

Response.Redirect("url", false);

This prevents the exception and seems to allow the cookie to be properly sent back to the client.

Just try to send a session variable when you press log in. And on the welcome page, first check whether that session is empty like this in the page load or in the Init Event:

if(Session["UserID"] == null || Session["UserID"] == "")
{
    Response.Redirect("Login.aspx");
}

For me, the following approach works. I think if there is any error after the "FormsAuthentication.SignOut()" statement, SingOut doesn't work.

public ActionResult SignOut()
    {
        if (Request.IsAuthenticated)
        {
            FormsAuthentication.SignOut();

            return Redirect("~/");
        }
        return View();
     }

Are you testing/seeing this behaviour using IE? It's possible that IE is serving up those pages from the cache. It is notoriously hard to get IE to flush it's cache, and so on many occasions, even after you log out, typing the url of one of the "secured" pages would show the cached content from before.

(I've seen this behaviour even when you log as a different user, and IE shows the "Welcome " bar at the top of your page, with the old user's username. Nowadays, usually a reload will update it, but if it's persistant, it could still be a caching issue.)

Doing Session.abandon() and destroying the cookie works pretty good. I'm using mvc3 and it looks like the problem occurs if you go to a protected page, log out, and go via your browser history. Not a big deal but still kinda of annoying.

Trying to go through links on my web app works the right way though.

Setting it to not do browser caching may be the way to go.

For MVC this works for me:

        public ActionResult LogOff()
        {
            FormsAuthentication.SignOut();
            return Redirect(FormsAuthentication.GetRedirectUrl(User.Identity.Name, true));
        }

I wanted to add some information to help understand the problem. Forms Authentication allows for storing user data either in a cookie, or in the query string of the URL. The method your site supports can be configured in the web.config file.

According to Microsoft:

The SignOut method removes the forms-authentication ticket information from the cookie or the URL if CookiesSupported is false.

At the same time, they say:

One of the HttpCookieMode values that indicates whether the application is configured for cookieless forms authentication. The default is UseDeviceProfile.

Lastly, regarding UseDeviceProfile, they say:

If the CookieMode property is set to UseDeviceProfile, the CookiesSupported property will return true if the Browser for the current Request supports both cookies and redirecting with cookies; otherwise, the CookiesSupported property will return false.

Piecing this all together, depending on the user's browser, the default configuration may result in CookiesSupported being true, which means the SignOut method doesn't clear the ticket from the cookie. This seems counter-intuitive and I don't know why it works this way -- I would expect SignOut to actually sign the user out under any circumstances.

One way to make the SignOut work by itself is to change the cookie mode to "UseCookies" (i.e. cookies are required) in the web.config file:

<authentication mode="Forms">
  <forms loginUrl="~/Account/SignIn" cookieless="UseCookies"/>
</authentication>

According to my tests, doing this makes SignOut work by itself at the cost of your site now requiring cookies to function properly.

Be aware that WIF refuses to tell the browser to cleanup the cookies if the wsignoutcleanup message from STS doesn't match the url with the name of the application from IIS, and I mean CASE SENSITIVE. WIF responds with the green OK check, but will not send the command to delete cookies to browser.

So, you need to pay attention to the case sensitivity of your url's.

For example, ThinkTecture Identity Server saves the urls of the visiting RPs in one cookie, but it makes all of them lower case. WIF will receive the wsignoutcleanup message in lower case and will compare it with the application name in IIS. If it doesn't match, it deletes no cookies, but will report OK to the browser. So, for this Identity Server I needed to write all urls in web.config and all application names in IIS in lower case, in order to avoid such problems.

Also don't forget to allow third party cookies in the browser if you have the applications outside of the subdomain of STS, otherwise the browser will not delete the cookies even if WIF tells him so.

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