Access ASP.NET authentication ticket on Client (via javascript) - asp.net

I have an ASP.NET website that uses Forms authentication
<authentication mode="Forms">
<forms name="NewsCoreAuthentication" loginUrl="~/Default.aspx" defaultUrl="~/Default.aspx" protection="Validation" timeout="300" domain="someRootDomain.com" />
</authentication>
I need to identify if user is authenticated on web page after it was rendered to client.
To accomplish this I thought that I can read document.cookie and check if ".ASPXAUTH" is there.
But the problem is that even if I am signed in this value is empty.
How can I check that user is authenticated?
Why document.cookie is empty?
Thank you for answers. blowdart helped me to understand why authentication ticket is not accessible from client script.

The reason it's blank is because the cookie is protected by being marked as HttpOnly. This means it cannot be accessed via script. Turning this off is a very very bad idea, as XSS vulnerabilities in your site could expose it to cookie theft, so I'm not going to tell you how you can do it.

As others have said, the auth ticket is and SHOULD be httponly.
The best way to do this is to use ApplicationServices. The JSON authentication endpoint exposes IsLoggedIn and I have noticed your concern regarding server load. The overhead of a call to a static endpoint that simply checks the cookie for you is negligible. Really.
So, If you are using MsAjax, just enable application services and call Sys.Services.AuthenticationService.IsLoggedIn.
If you want to do this from raw javascript here is the codez ;-)
Add this segment to you config file
<system.web>
------------
</system.web>
<system.web.extensions>
<scripting>
<webServices>
<authenticationService enabled ="true" requireSSL="false"/>
</webServices>
</scripting>
</system.web.extensions>
The page....
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<script type="text/javascript">
function createXHR() {
// a memoizing XMLHttpRequest factory.
var xhr;
var factories = [
function() { return new XMLHttpRequest(); },
function() { return new ActiveXObject("Msxml2.XMLHTTP"); },
function() { return new ActiveXObject("Msxml3.XMLHTTP"); },
function() { return new ActiveXObject("Microsoft.XMLHTTP"); } ];
for (var i = 0; i < factories.length; i++) {
try {
xhr = factories[i]();
// memoize the factory so we don't have to look for it again.
createXHR = factories[i];
return xhr;
} catch (e) { }
}
}
function isLoggedIn() {
var xhr = createXHR();
xhr.open("POST", "/Authentication_JSON_AppService.axd/IsLoggedIn", true);
xhr.onreadystatechange = function() {
if (this.readyState === 4) {
if (this.status != 200) {
alert(xhr.statusText);
} else {
alert("IsLoggedIn = " + xhr.responseText);
}
xhr = null;
}
};
xhr.setRequestHeader("content-type", "application/json");
xhr.send(null);
}
</script>
</head>
<body>
<input type="button" value="IsLoggedIn?" onclick="isLoggedIn()" />
</body>
</html>

Number one... this is a bad idea. There is absolutely no security in checking if a user is authorized on the client side. None.
But if you really want to do this... do the check in code behind, and push a value to the client that can be read via Javascript. Something akin to:
RegisterClientScript("isvalidated", "var isUserAuthenticated = " + UserAuthenticated);
You see the problem now? You could do the same thing in AJAX... but it has the same problem.
OK, I can see doing this as a simple convenience for the user... showing certain links if they are authorized for instance. But it is not secure in any way shape or form. Just do yourself a favor and handle this in code-behind.

Related

How to prevent users from going back to the previous page?

I am using ASP.NET MVC (latest version).
Imagine having 2 pages:
Page-1: "Enter data" >> Page-2: "Thank you"
After submitting Page-1 you are being redirected to Page-2.
My goal: I want to make sure that you can't go back to Page-1 when you hit the browser's back button once you made it to Page-2. Instead I want you rather to stay on Page-2 (or being pushed forward to Page-2 every time you hit the back button).
I have tried all different kind of things. The following is just some simplified pseudo code ...
[NoBrowserCache]
public ActionResult Page1(int userId)
{
var user = GetUserFromDb(userId);
if (user.HasAlreadySubmittedPage1InThePast)
{
// forward to page 2
return RedirectToAction("Page2", routeValues: new { userId = userId });
}
var model = new Page1Model();
return View("Page1", model);
}
[NoBrowserCache]
[HttpPost]
public ActionResult Page1(Page1Model model)
{
var user = GetUserFromDb(model.UserId);
if (user.HasAlreadySubmittedPage1InThePast)
{
// forward to page 2
return RedirectToAction("Page2", routeValues: new { userId = model.UserId });
}
// Save posted data to the db
// ...
return RedirectToAction("Page2", routeValues: new { userId = model.UserId });
}
public class NoBrowserCache : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
// Haha ... tried everything I found on the web here:
// Make sure the requested page is not put in the browser cache.
filterContext.HttpContext.Response.Cache.SetCacheability(HttpCacheability.NoCache);
filterContext.HttpContext.Response.Cache.SetNoStore();
filterContext.HttpContext.Response.Cache.AppendCacheExtension("no-cache");
filterContext.HttpContext.Response.Cache.SetExpires(DateTime.Now);
filterContext.HttpContext.Response.Expires = 0;
}
}
If only I could make sure that a request is being sent to the server every time I hit the back button. But right now, clicking the back button just pulls Page-1 from my browser's cache without sending a request to the server. So currently, I have no chance to redirect you forward to Page-2 by server means.
Any ideas or suggestions?
Thanks, guys!
Btw: There is no login/authentication involved. So, I can't use Session.Abandon() or stuff like this. And I would rather use some server based code than javascript if possible.
EDIT 2017-5-12
Following #grek40, I made sure that the anti-chaching statements end up in the browser. I therefor completely removed the [NoBrowserCache]-ActionFilterAttribute from my C# code above. Instead I added the following statements in the <head> section of my _Layout.cshtml:
<meta http-equiv="Cache-Control" content="no-cache, no-store, must-revalidate">
<meta http-equiv="Pragma" content="no-cache">
<meta http-equiv="Expires" content="0">
I confirm that these three lines are being rendered to my browser (used my browser's developer tools to inspect). However, caching still works. I can still move backward without any server requests. Tested this with Google Chrome v62, Firefox Quantum v57 and Microsoft Edge v41 (all on Win10). #
EDIT 2017-6-12
Again following #grek40's suggestions: tried Expires: 0 as well as Expires: -1. No difference. I still didn't manage, to turn off my browser's cache.
Finally I found a solution. It's javascript based, but very simple.
I just had to add the following snippet to my Page-2 (the page I don't want users to leave anymore once they got there):
<script type="text/javascript">
$(document).ready(function () {
history.pushState({ page: 1 }, "title 1", "#nbb");
window.onhashchange = function (event) {
window.location.hash = "nbb";
};
});
I found this here: how to stop browser back button using javascript
Thanks to all your support guys. But "my own" solution was the only one that worked.
This can be done by using javascript. Use the following code
<script type = "text/javascript" >
function preventBack(){window.history.forward();}
setTimeout("preventBack()", 0);
window.onunload=function(){null};
</script>
or check the following link1 and link2.
This little piece of code might help you in solving your issue.
<script type="text/javascript">
/*To retain on the same view on Back Click*/
history.pushState(null, null, window.location.href);
window.addEventListener('popstate', function (event) {
history.pushState(null, null, window.location.href);
event.preventDefault();
});
</script>
You can add a line of javascript to every page for a client-side solution:
history.forward();
See docs on MDN. When there is a page to go forward to (which is when the used pressed the BACK button), this will force the user to that page. When the user already is at the most recent page, this does nothing (no error).
Response.Cache.SetCacheability(HttpCacheability.NoCache); // HTTP 1.1.
Response.Cache.AppendCacheExtension("no-store, must-revalidate");
Response.AppendHeader("Pragma", "no-cache"); // HTTP 1.0.
Response.AppendHeader("Expires", "0"); // Proxies.

how does the meteor-accounts oauth workflow happen

I'm trying to use accounts-facebook with the Ionic CLI. I'm using a client side bundler script but I can't get the entire oauth workflow to complete.
I set up a standard account-facebook config from the meteor-angular-socially project and discovered that I'm getting stuck at the oauth redirect URI. The following method is never called in my client-side bundle
// in script: oauth/oauth_client.js
// Called by the popup when the OAuth flow is completed, right before
// the popup closes.
OAuth._handleCredentialSecret = function (credentialToken, secret) {
check(credentialToken, String);
check(secret, String);
if (! _.has(credentialSecrets,credentialToken)) {
credentialSecrets[credentialToken] = secret;
} else {
throw new Error("Duplicate credential token from OAuth login");
}
};
I get the following redirect URL from oauth which should load this page
# http://localhost:3000/_oauth/facebook/?code=[...]&state=[...]
<!DOCTYPE html>
<html>
<body>
<p id="completedText" style="display:none;">
Login completed. <a href="#" id="loginCompleted">
Click here</a> to close this window.
</p>
<div id="config" style="display:none;">{
"setCredentialToken":false,
"storagePrefix":"Meteor.oauth.credentialSecret-",
"isCordova":false
}</div>
<script type="text/javascript" src="/_oauth/facebook/end_of_popup_response.js">
# script included inline for ease of reading
(function () {
var config = JSON.parse(document.getElementById("config").innerHTML);
if (config.setCredentialToken) {
var credentialToken = config.credentialToken;
var credentialSecret = config.credentialSecret;
if (config.isCordova) {
var credentialString = JSON.stringify({
credentialToken: credentialToken,
credentialSecret: credentialSecret
});
window.location.hash = credentialString;
}
if (window.opener && window.opener.Package &&
window.opener.Package.oauth) {
window.opener.Package.oauth.OAuth._handleCredentialSecret(
credentialToken, credentialSecret);
} else {
try {
localStorage[config.storagePrefix + credentialToken] = credentialSecret;
} catch (err) {
// We can't do much else, but at least close the popup instead
// of having it hang around on a blank page.
}
}
}
if (! config.isCordova) {
document.getElementById("completedText").style.display = "block";
document.getElementById("loginCompleted").onclick = function(){ window.close(); };
window.close();
}
})();
</script>
</body>
</html>
In the standard meteor CLI config, somehow/somwhere config.setCredentialToken === true and config.setCredentialToken and config.credentialSecret are set. But I cannot figure out where/when that happens.
In my accounts-facebook-client-side.bundle.js, none of this happens.
update
I realized that the magic happens on the Meteor server side. If I set my oauth redirect_uri to the port where the Meteor server is running, then I get the following in the ./_oauth/facebook page:
<div id="config" style="display:none;">{
"setCredentialToken":true,
"credentialToken":"bsgEZrFbK-UruR1iX81dEitIR0t5nC_a1HM4-EGSGx5",
"credentialSecret":"hi8rJxbyOsI0gVaoIHrr7N9kH9k2Fku1DYQXP5BmQMt",
"storagePrefix":"Meteor.oauth.credentialSecret-",
"isCordova":false
}</div>
BUT, I am guessing if I do that, I won't be able to read these values from localstorage(?) on my web.browser client page (port 3000)
any ideas for a workaround?
Simplest way to fix it is to put nginx in front of your app and use proxy_pass to sort calls towards Ionic's server and Meteor's server based on path:
server {
listen 80;
server_name domain.tld;
location / {
proxy_pass http://domain.tld:8100;
}
location /_oauth {
proxy_pass http://domain.tld:3000;
}
location /packages {
proxy_pass http://domain.tld:3000;
}
}
I just tried this method with accounts-facebook and works flawlessly (you will need to point your browser to http://domain.tld:80 instead of http://domain.tld:8100), but I already started digging deeper into Meteor's code to see if I can accomplish something better. I will edit this answer if I will find a better solution.

ASP.NET - Uploadify works in IE, not in FF (Auth Cookies

i have a WebForms application, and am trying to use the uploadify jquery library.
It works fine in IE8, but doesn't in FF7, FF10, or FF3. The break point i put in Upload.ashx is not hit.
I did quite the search and found that it has to does with cookies, something like ASPXAUTH. I tried adding it to 'scriptData', but no success.
Any ideas?
Page code:
<script type="text/javascript">
$(document).ready(function () {
alert($(".hidcook").val());
// <![CDATA[
var id = "55";
var theString = "asdf";
$('#fileInput').uploadify({
'uploader': 'uploadify/uploadify.swf',
'script': 'Upload.ashx',
'scriptData': { 'id': id, 'foo': theString },
'cancelImg': 'uploadify/cancel.png',
'auto': true,
'multi': true,
'fileDesc': 'All Files',
'queueSizeLimit': 90,
'buttonText': 'Importar Planilha',
'folder': '/uploads',
'onAllComplete': function (event, queueID, fileObj, response, data) {
}
});
});
// ]]></script>
Upload.ashx:
public class Upload : IHttpHandler, IRequiresSessionState{
public void ProcessRequest(HttpContext context)
{
try
{
HttpPostedFile file = context.Request.Files["Filedata"]; //breakpoint
int id = (Int32.Parse(context.Request["id"]));
string foo = context.Request["foo"];
file.SaveAs("C:\\" + id.ToString() + foo + file.FileName);
context.Response.Write("1");
}
catch (Exception ex)
{
context.Response.Write("0");
}
}
If your website content is not public, add to web.config authorization access to the Handler.
<location path="Upload.ashx">
<system.web>
<authorization>
<allow users="*"/>
</authorization>
</system.web>
</location>
There are some differences in how browsers implement file upload through flash component.
IE uses the same session. FF opens a new connection, so the server sees an un-authenticaded user that is trying to access a protected page.
I had an issue using MVC where uploadify didn't post to the controller action.
It was due to an authentication issue. Flash for some reason creates it's own separate cookie to the browser, so if the user has already been authenticated with the browser (ASPXAUTH) cookie, and then the swf file makes a separate request using it's own flash cookie (which has not been authenticated.
Run fiddler to see whats happening, you may find that the server request that the uploadify is making is being redirected to the login.aspx page.
Although I don't know why this would work in just IE?

How to log out user from web site using BASIC authentication?

Is it possible to log out user from a web site if he is using basic authentication?
Killing session is not enough, since, once user is authenticated, each request contains login info, so user is automatically logged in next time he/she access the site using the same credentials.
The only solution so far is to close browser, but that's not acceptable from the usability standpoint.
Have the user click on a link to https://log:out#example.com/. That will overwrite existing credentials with invalid ones; logging them out.
This does so by sending new credentials in the URL. In this case user="log" password="out".
An addition to the answer by bobince ...
With Ajax you can have your 'Logout' link/button wired to a Javascript function. Have this function send the XMLHttpRequest with a bad username and password. This should get back a 401. Then set document.location back to the pre-login page. This way, the user will never see the extra login dialog during logout, nor have to remember to put in bad credentials.
Basic Authentication wasn't designed to manage logging out. You can do it, but not completely automatically.
What you have to do is have the user click a logout link, and send a ‘401 Unauthorized’ in response, using the same realm and at the same URL folder level as the normal 401 you send requesting a login.
They must be directed to input wrong credentials next, eg. a blank username-and-password, and in response you send back a “You have successfully logged out” page. The wrong/blank credentials will then overwrite the previous correct credentials.
In short, the logout script inverts the logic of the login script, only returning the success page if the user isn't passing the right credentials.
The question is whether the somewhat curious “don't enter your password” password box will meet user acceptance. Password managers that try to auto-fill the password can also get in the way here.
Edit to add in response to comment: re-log-in is a slightly different problem (unless you require a two-step logout/login obviously). You have to reject (401) the first attempt to access the relogin link, than accept the second (which presumably has a different username/password). There are a few ways you could do this. One would be to include the current username in the logout link (eg. /relogin?username), and reject when the credentials match the username.
You can do it entirely in JavaScript:
IE has (for a long time) standard API for clearing Basic Authentication cache:
document.execCommand("ClearAuthenticationCache")
Should return true when it works. Returns either false, undefined or blows up on other browsers.
New browsers (as of Dec 2012: Chrome, FireFox, Safari) have "magic" behavior. If they see a successful basic auth request with any bogus other username (let's say logout) they clear the credentials cache and possibly set it for that new bogus user name, which you need to make sure is not a valid user name for viewing content.
Basic example of that is:
var p = window.location.protocol + '//'
// current location must return 200 OK for this GET
window.location = window.location.href.replace(p, p + 'logout:password#')
An "asynchronous" way of doing the above is to do an AJAX call utilizing the logout username. Example:
(function(safeLocation){
var outcome, u, m = "You should be logged out now.";
// IE has a simple solution for it - API:
try { outcome = document.execCommand("ClearAuthenticationCache") }catch(e){}
// Other browsers need a larger solution - AJAX call with special user name - 'logout'.
if (!outcome) {
// Let's create an xmlhttp object
outcome = (function(x){
if (x) {
// the reason we use "random" value for password is
// that browsers cache requests. changing
// password effectively behaves like cache-busing.
x.open("HEAD", safeLocation || location.href, true, "logout", (new Date()).getTime().toString())
x.send("")
// x.abort()
return 1 // this is **speculative** "We are done."
} else {
return
}
})(window.XMLHttpRequest ? new window.XMLHttpRequest() : ( window.ActiveXObject ? new ActiveXObject("Microsoft.XMLHTTP") : u ))
}
if (!outcome) {
m = "Your browser is too old or too weird to support log out functionality. Close all windows and restart the browser."
}
alert(m)
// return !!outcome
})(/*if present URI does not return 200 OK for GET, set some other 200 OK location here*/)
You can make it a bookmarklet too:
javascript:(function (c) {
var a, b = "You should be logged out now.";
try {
a = document.execCommand("ClearAuthenticationCache")
} catch (d) {
}
a || ((a = window.XMLHttpRequest ? new window.XMLHttpRequest : window.ActiveXObject ? new ActiveXObject("Microsoft.XMLHTTP") : void 0) ? (a.open("HEAD", c || location.href, !0, "logout", (new Date).getTime().toString()), a.send(""), a = 1) : a = void 0);
a || (b = "Your browser is too old or too weird to support log out functionality. Close all windows and restart the browser.");
alert(b)
})(/*pass safeLocation here if you need*/);
The following function is confirmed working for Firefox 40, Chrome 44, Opera 31 and IE 11.
Bowser is used for browser detection, jQuery is also used.
- secUrl is the url to a password protected area from which to log out.
- redirUrl is the url to a non password protected area (logout success page).
- you might wish to increase the redirect timer (currently 200ms).
function logout(secUrl, redirUrl) {
if (bowser.msie) {
document.execCommand('ClearAuthenticationCache', 'false');
} else if (bowser.gecko) {
$.ajax({
async: false,
url: secUrl,
type: 'GET',
username: 'logout'
});
} else if (bowser.webkit) {
var xmlhttp = new XMLHttpRequest();
xmlhttp.open("GET", secUrl, true);
xmlhttp.setRequestHeader("Authorization", "Basic logout");
xmlhttp.send();
} else {
alert("Logging out automatically is unsupported for " + bowser.name
+ "\nYou must close the browser to log out.");
}
setTimeout(function () {
window.location.href = redirUrl;
}, 200);
}
Here's a very simple Javascript example using jQuery:
function logout(to_url) {
var out = window.location.href.replace(/:\/\//, '://log:out#');
jQuery.get(out).error(function() {
window.location = to_url;
});
}
This log user out without showing him the browser log-in box again, then redirect him to a logged out page
This isn't directly possible with Basic-Authentication.
There's no mechanism in the HTTP specification for the server to tell the browser to stop sending the credentials that the user already presented.
There are "hacks" (see other answers) typically involving using XMLHttpRequest to send an HTTP request with incorrect credentials to overwrite the ones originally supplied.
Just for the record, there is a new HTTP Response Header called Clear-Site-Data. If your server reply includes a Clear-Site-Data: "cookies" header, then the authentication credentials (not only cookies) should be removed. I tested it on Chrome 77 but this warning shows on the console:
Clear-Site-Data header on 'https://localhost:9443/clear': Cleared data types:
"cookies". Clearing channel IDs and HTTP authentication cache is currently not
supported, as it breaks active network connections.
And the auth credentials aren't removed, so this doesn't works (for now) to implement basic auth logouts, but maybe in the future will. Didn't test on other browsers.
References:
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Clear-Site-Data
https://www.w3.org/TR/clear-site-data/
https://github.com/w3c/webappsec-clear-site-data
https://caniuse.com/#feat=mdn-http_headers_clear-site-data_cookies
It's actually pretty simple.
Just visit the following in your browser and use wrong credentials:
http://username:password#yourdomain.com
That should "log you out".
This is working for IE/Netscape/Chrome :
function ClearAuthentication(LogOffPage)
{
var IsInternetExplorer = false;
try
{
var agt=navigator.userAgent.toLowerCase();
if (agt.indexOf("msie") != -1) { IsInternetExplorer = true; }
}
catch(e)
{
IsInternetExplorer = false;
};
if (IsInternetExplorer)
{
// Logoff Internet Explorer
document.execCommand("ClearAuthenticationCache");
window.location = LogOffPage;
}
else
{
// Logoff every other browsers
$.ajax({
username: 'unknown',
password: 'WrongPassword',
url: './cgi-bin/PrimoCgi',
type: 'GET',
beforeSend: function(xhr)
{
xhr.setRequestHeader("Authorization", "Basic AAAAAAAAAAAAAAAAAAA=");
},
error: function(err)
{
window.location = LogOffPage;
}
});
}
}
$(document).ready(function ()
{
$('#Btn1').click(function ()
{
// Call Clear Authentication
ClearAuthentication("force_logout.html");
});
});
All you need is redirect user on some logout URL and return 401 Unauthorized error on it. On error page (which must be accessible without basic auth) you need to provide a full link to your home page (including scheme and hostname). User will click this link and browser will ask for credentials again.
Example for Nginx:
location /logout {
return 401;
}
error_page 401 /errors/401.html;
location /errors {
auth_basic off;
ssi on;
ssi_types text/html;
alias /home/user/errors;
}
Error page /home/user/errors/401.html:
<!DOCTYPE html>
<p>You're not authorised. Login.</p>
I've just tested the following in Chrome (79), Firefox (71) and Edge (44) and it works fine. It applies the script solution as others noted above.
Just add a "Logout" link and when clicked return the following html
<div>You have been logged out. Redirecting to home...</div>
<script>
var XHR = new XMLHttpRequest();
XHR.open("GET", "/Home/MyProtectedPage", true, "no user", "no password");
XHR.send();
setTimeout(function () {
window.location.href = "/";
}, 3000);
</script>
add this to your application :
#app.route('/logout')
def logout():
return ('Logout', 401, {'WWW-Authenticate': 'Basic realm="Login required"'})
function logout() {
var userAgent = navigator.userAgent.toLowerCase();
if (userAgent.indexOf("msie") != -1) {
document.execCommand("ClearAuthenticationCache", false);
}
xhr_objectCarte = null;
if(window.XMLHttpRequest)
xhr_object = new XMLHttpRequest();
else if(window.ActiveXObject)
xhr_object = new ActiveXObject("Microsoft.XMLHTTP");
else
alert ("Your browser doesn't support XMLHTTPREQUEST");
xhr_object.open ('GET', 'http://yourserver.com/rep/index.php', false, 'username', 'password');
xhr_object.send ("");
xhr_object = null;
document.location = 'http://yourserver.com';
return false;
}
function logout(url){
var str = url.replace("http://", "http://" + new Date().getTime() + "#");
var xmlhttp;
if (window.XMLHttpRequest) xmlhttp=new XMLHttpRequest();
else xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4) location.reload();
}
xmlhttp.open("GET",str,true);
xmlhttp.setRequestHeader("Authorization","Basic xxxxxxxxxx")
xmlhttp.send();
return false;
}
Based on what I read above I got a simple solution that works on any browser:
1) on you logout page you call an ajax to your login back end. Your login back end must accept logout user. Once the back end accept, the browser clear the current user and assumes the "logout" user.
$.ajax({
async: false,
url: 'http://your_login_backend',
type: 'GET',
username: 'logout'
});
setTimeout(function () {
window.location.href = 'http://normal_index';
}, 200);
2) Now when the user got back to the normal index file it will try to automatic enter in the system with the user "logout", on this second time you must block it by reply with 401 to invoke the login/password dialog.
3) There are many ways to do that, I created two login back ends, one that accepts the logout user and one that doesn't. My normal login page use the one that doesn't accept, my logout page use the one that accepts it.
Sending https://invalid_login#hostname works fine everywhere except Safari on Mac (well, not checked Edge but should work there too).
Logout doesn't work in Safari when a user selects 'remember password' in the HTTP Basic Authentication popup. In this case the password is stored in Keychain Access (Finder > Applications > Utilities > Keychain Access (or CMD+SPACE and type "Keychain Access")). Sending https://invalid_login#hostname doesn't affect Keychain Access, so with this checkbox it is not possible to logout on Safari on Mac. At least it is how it works for me.
MacOS Mojave (10.14.6), Safari 12.1.2.
The code below works fine for me in Firefox (73), Chrome (80) and Safari (12). When a user navigates to a logout page the code is executed and drops the credentials.
//It should return 401, necessary for Safari only
const logoutUrl = 'https://example.com/logout';
const xmlHttp = new XMLHttpRequest();
xmlHttp.open('POST', logoutUrl, true, 'logout');
xmlHttp.send();
Also for some reason Safari doesn't save credentials in the HTTP Basic Authentication popup even when the 'remember password' is selected. The other browsers do this correctly.
This JavaScript must be working for all latest version browsers:
//Detect Browser
var isOpera = !!window.opera || navigator.userAgent.indexOf(' OPR/') >= 0;
// Opera 8.0+ (UA detection to detect Blink/v8-powered Opera)
var isFirefox = typeof InstallTrigger !== 'undefined'; // Firefox 1.0+
var isSafari = Object.prototype.toString.call(window.HTMLElement).indexOf('Constructor') > 0;
// At least Safari 3+: "[object HTMLElementConstructor]"
var isChrome = !!window.chrome && !isOpera; // Chrome 1+
var isIE = /*#cc_on!#*/false || !!document.documentMode; // At least IE6
var Host = window.location.host;
//Clear Basic Realm Authentication
if(isIE){
//IE
document.execCommand("ClearAuthenticationCache");
window.location = '/';
}
else if(isSafari)
{//Safari. but this works mostly on all browser except chrome
(function(safeLocation){
var outcome, u, m = "You should be logged out now.";
// IE has a simple solution for it - API:
try { outcome = document.execCommand("ClearAuthenticationCache") }catch(e){}
// Other browsers need a larger solution - AJAX call with special user name - 'logout'.
if (!outcome) {
// Let's create an xmlhttp object
outcome = (function(x){
if (x) {
// the reason we use "random" value for password is
// that browsers cache requests. changing
// password effectively behaves like cache-busing.
x.open("HEAD", safeLocation || location.href, true, "logout", (new Date()).getTime().toString())
x.send("");
// x.abort()
return 1 // this is **speculative** "We are done."
} else {
return
}
})(window.XMLHttpRequest ? new window.XMLHttpRequest() : ( window.ActiveXObject ? new ActiveXObject("Microsoft.XMLHTTP") : u ))
}
if (!outcome) {
m = "Your browser is too old or too weird to support log out functionality. Close all windows and restart the browser."
}
alert(m);
window.location = '/';
// return !!outcome
})(/*if present URI does not return 200 OK for GET, set some other 200 OK location here*/)
}
else{
//Firefox,Chrome
window.location = 'http://log:out#'+Host+'/';
}
type chrome://restart in the address bar and chrome, with all its apps that are running in background, will restart and the Auth password cache will be cleaned.
This is how my logout is working using form:
create basic auth user logout with password logout
create folder logout/ and add .htaccess: with line 'require user logout'
RewriteEngine On
AuthType Basic
AuthName "Login"
AuthUserFile /mypath/.htpasswd
require user logout
add logout button to website as form like:
<form action="https://logout:logout#example.com/logout/" method="post">
<button type="submit">Logout</button>
</form>
logout/index.php could be something like:
<?php
echo "LOGOUT SUCCESS";
header( "refresh:2; url=https://example.com" );
?>
5.9.2022 confirmed working on chrome, edge and samsung android internet browser
use a session ID (cookie)
invalidate the session ID on the server
Don't accept users with invalid session IDs
I updated mthoring's solution for modern Chrome versions:
function logout(secUrl, redirUrl) {
if (bowser.msie) {
document.execCommand('ClearAuthenticationCache', 'false');
} else if (bowser.gecko) {
$.ajax({
async: false,
url: secUrl,
type: 'GET',
username: 'logout'
});
} else if (bowser.webkit || bowser.chrome) {
var xmlhttp = new XMLHttpRequest();
xmlhttp.open(\"GET\", secUrl, true);
xmlhttp.setRequestHeader(\"Authorization\", \"Basic logout\");\
xmlhttp.send();
} else {
// http://stackoverflow.com/questions/5957822/how-to-clear-basic-authentication-details-in-chrome
redirUrl = url.replace('http://', 'http://' + new Date().getTime() + '#');
}
setTimeout(function () {
window.location.href = redirUrl;
}, 200);
}
As others have said, we need to get the same URL and send an error (e.g., 401: StatusUnauthorized something like that), and that's it.
And I use the Get method to let it know I need to logout,
Here is a full example of writing with golang.
package main
import (
"crypto/subtle"
"fmt"
"log"
"net/http"
)
func BasicAuth(username, password, realm string, handlerFunc http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
queryMap := r.URL.Query()
if _, ok := queryMap["logout"]; ok { // localhost:8080/public/?logout
w.WriteHeader(http.StatusUnauthorized) // 401
_, _ = w.Write([]byte("Success logout!\n"))
return
}
user, pass, ok := r.BasicAuth()
if !ok ||
subtle.ConstantTimeCompare([]byte(user), []byte(username)) != 1 ||
subtle.ConstantTimeCompare([]byte(pass), []byte(password)) != 1 {
// https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/WWW-Authenticate
w.Header().Set("WWW-Authenticate", `Basic realm="`+realm+`", charset="UTF-8"`)
w.WriteHeader(http.StatusUnauthorized)
_, _ = w.Write([]byte("Unauthorised.\n"))
return
}
handlerFunc(w, r)
}
}
type UserInfo struct {
name string
psw string
}
func main() {
portNumber := "8080"
guest := UserInfo{"guest", "123"}
// localhost:8080/public/ -> ./public/everyone
publicHandler := http.StripPrefix(
"/public/", http.FileServer(http.Dir("./public/everyone")),
)
publicHandlerFunc := func(w http.ResponseWriter, r *http.Request) {
switch r.Method {
case http.MethodGet:
publicHandler.ServeHTTP(w, r)
/*
case http.MethodPost:
case http.MethodPut:
case http.MethodDelete:
*/
default:
return
}
}
http.HandleFunc("/public/",
BasicAuth(guest.name, guest.psw, "Please enter your username and password for this site",
publicHandlerFunc),
)
log.Fatal(http.ListenAndServe(fmt.Sprintf(":%s", portNumber), nil))
}
When you have already logout, then you need to refresh (F5) the page. Otherwise, you may see the old content.
Actually I think basic authentication was intended to be used with static pages, not for any sophisticated session management or CGI pages.
Thus when wanting session management you should design a classic "login form" to query for user and password (maybe 2nd factor as well).
The CGI form handler should convert successful authentication to a session (ID) that is remembered on the server and (in a cookie or as part of the URI).
Then logout can be implemented simply by making the server (and client) "forget" the session.
The other advantage is that (even when encrypted) the user and password is not send with every request to the server (instead the session ID would be sent).
If the session ID on the server is combined with a timestamp for the "last action" performed, then session timeout could be implemented by comparing that timestamp with the current time:
If the time span is too large, "timeout" the session by forgetting the session ID.
Any request to an invalid session would cause a redirection to the login page (or maybe if you want to make it more comfortable, you can have a "revalidation form" that requests the password again, too).
As a proof of concept I had implemented a completely cookie-free session management that is purely URI-based (the session ID is always part of the URI).
However the complete code would be too long for this answer.
Special care about performance has to be taken when wanting to handle several thousands of concurrent sessions.
For anyone who use Windows Authentication (also known as Negotiate, Kerberos, or NTLM authentication), I use ASP.NET Core with Angular.
I found an efficient manner to change users !
I modify my login method on the javascript side like that :
protected login(changeUser: boolean = false): Observable<AuthInfo> {
let params = new HttpParams();
if(changeUser) {
let dateNow = this.datePipe.transform(new Date(), 'yyyy-MM-dd HH:mm:ss');
params = params.set('changeUser', dateNow!);
}
const url: string = `${environment.yourAppsApiUrl}/Auth/login`;
return this.http.get<AuthInfo>(url, { params: params });
}
Here is my method on the backend :
[Route("api/[controller]")]
[ApiController]
[Produces("application/json")]
[Authorize(AuthenticationSchemes = NegotiateDefaults.AuthenticationScheme)]
public class AuthController : Controller
{
[HttpGet("login")]
public async Task<IActionResult> Login(DateTime? changeUser = null)
{
if (changeUser > DateTime.Now.AddSeconds(-3))
return Unauthorized();
...
... (login process)
...
return Ok(await _authService.GetToken());
}
}
return Unauthorized() return the 401 code that causes the browser identification popup window to appear, here is the process :
I transmit the date now as a parameter if I want to change user.
I return the 401 code if no more than 3 seconds have passed since that moment Now.
I complete my credential and the same request with the same parameter is sent to the backend.
Since more than 3 seconds have passed, I continue the login process but this time with the new credential !
function logout(secUrl, redirUrl) {
if (bowser.msie) {
document.execCommand('ClearAuthenticationCache', 'false');
} else if (bowser.gecko) {
$.ajax({
async: false,
url: secUrl,
type: 'GET',
username: 'logout'
});
} else if (bowser.webkit) {
var xmlhttp = new XMLHttpRequest();
xmlhttp.open("GET", secUrl, true);
xmlhttp.setRequestHeader("Authorization", "Basic logout");
xmlhttp.send();
} else {
alert("Logging out automatically is unsupported for " + bowser.name
+ "\nYou must close the browser to log out.");
}
setTimeout(function () {
window.location.href = redirUrl;
}, 200);
}
I tried using the above in the following way.
?php
ob_start();
session_start();
require_once 'dbconnect.php';
// if session is not set this will redirect to login page
if( !isset($_SESSION['user']) ) {
header("Location: index.php");
exit;
}
// select loggedin users detail
$res=mysql_query("SELECT * FROM users WHERE userId=".$_SESSION['user']);
$userRow=mysql_fetch_array($res);
?>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Welcome - <?php echo $userRow['userEmail']; ?></title>
<link rel="stylesheet" href="assets/css/bootstrap.min.css" type="text/css" />
<link rel="stylesheet" href="style.css" type="text/css" />
<script src="assets/js/bowser.min.js"></script>
<script>
//function logout(secUrl, redirUrl)
//bowser = require('bowser');
function logout(secUrl, redirUrl) {
alert(redirUrl);
if (bowser.msie) {
document.execCommand('ClearAuthenticationCache', 'false');
} else if (bowser.gecko) {
$.ajax({
async: false,
url: secUrl,
type: 'GET',
username: 'logout'
});
} else if (bowser.webkit) {
var xmlhttp = new XMLHttpRequest();
xmlhttp.open("GET", secUrl, true);
xmlhttp.setRequestHeader("Authorization", "Basic logout");
xmlhttp.send();
} else {
alert("Logging out automatically is unsupported for " + bowser.name
+ "\nYou must close the browser to log out.");
}
window.location.assign(redirUrl);
/*setTimeout(function () {
window.location.href = redirUrl;
}, 200);*/
}
function f1()
{
alert("f1 called");
//form validation that recalls the page showing with supplied inputs.
}
</script>
</head>
<body>
<nav class="navbar navbar-default navbar-fixed-top">
<div class="container">
<div class="navbar-header">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="http://www.codingcage.com">Coding Cage</a>
</div>
<div id="navbar" class="navbar-collapse collapse">
<ul class="nav navbar-nav">
<li class="active">Back to Article</li>
<li>jQuery</li>
<li>PHP</li>
</ul>
<ul class="nav navbar-nav navbar-right">
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false">
<span class="glyphicon glyphicon-user"></span> Hi' <?php echo $userRow['userEmail']; ?> <span class="caret"></span></a>
<ul class="dropdown-menu">
<li><span class="glyphicon glyphicon-log-out"></span> Sign Out</li>
</ul>
</li>
</ul>
</div><!--/.nav-collapse -->
</div>
</nav>
<div id="wrapper">
<div class="container">
<div class="page-header">
<h3>Coding Cage - Programming Blog</h3>
</div>
<div class="row">
<div class="col-lg-12" id="div_logout">
<h1 onclick="logout(window.location.href, 'www.espncricinfo.com')">MichaelA1S1! Click here to see log out functionality upon click inside div</h1>
</div>
</div>
</div>
</div>
<script src="assets/jquery-1.11.3-jquery.min.js"></script>
<script src="assets/js/bootstrap.min.js"></script>
</body>
</html>
<?php ob_end_flush(); ?>
But it only redirects you to new location. No logout.

Is there a better and/or easier way to do a logout?

Here is the situation:
User logs in via username/password stored in an MSSQL database
If the user is authenticated, the system makes a session variable with username/SHA1'd password and boolean if the user is logged in or not (for subsequent pages)
I need to be able to destroy the session variable. I want a confirmation box as well.
This is what I have so far:
<script type="text/javascript">
//<![CDATA[
function doLogout() {
try {
var conf = false;
conf = confirm("Really log out?");
if (conf === true) {
$.post("logout.aspx");
}
} catch (ex) {
alert(ex);
}
}
//]]>
</script>
Since it is an ajax request won't reload the page (the functionality works fine, the request destroys the session), I think I need a different approach to do this. I would really like to be able to do it all in ASP.NET if possible.
Any solution is welcome, as long as #3 above is fulfilled.
Well, for starters your solution depends on the user having Javascript, if they don't they won't be able to logout. I don't think you should be using AJAX for this, just a simple link/button to logout.aspx would be fine, that could then correctly redirect them to the homepage with the 'logged-out' state set. You could then use some unobtrusive Javascript to add the confirmation.
jQuery version (since you mentioned that):
Logout
<script type="text/javascript">
//<![CDATA[
$(document).ready(function() {
$('#logout-link').click(function () {
return confirm("Really log out?");
});
});
//]]>
</script>
pure-Javascript version:
Logout
<script type="text/javascript">
//<![CDATA[
window.onload = function() {
if(!document.getElementById) return;
document.getElementById('logout-link').onclick(function() {
return confirm("Really log out?");
});
}
//]]>
</script>

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