SAML 2.0 Single Log Out Best Practices Following Service Provider Inactivity

Understanding SAML 2.0 Single Log Out After Session Timeout

Because SAML 2.0 Single Sign-On (SSO) systems allow users to sign into various applications using a single set of credentials, they have considerably simplified user authentication. But there are also significant issues with the Single Log Out (SLO) notion, especially with regard to what occurs when a user's session expires at a Service Provider (SP) since they haven't logged in. In this case, should the Identity Provider (IDP) session end as well?

Session management between the SP and IDP is essential to ensuring safe and efficient access in the context of SAML 2.0. It's not always obvious when an SP session ends if the user should still be connected to the IDP, which could have an impact on other apps that are linked to the same IDP. This raises questions about usability as well as security.

A clear best practice for handling these session timeouts needs to be established by many businesses, particularly those that use interfaces like Microsoft Entra. Is it better for an SP's session to stop simply at the SP level, or should it also result in a SLO that logs the user out of their IDP account?

Using real-world examples to illustrate the most efficient techniques for handling session timeouts and guaranteeing both security and usability, this paper examines standard practices and standards for handling SAML 2.0 SLO events in such situations.

Command	Example of use
session()	Utilized in the Express application to control user sessions. In the example, it assists in monitoring user activity and session timeouts so that logout logic can be triggered when needed.
maxAge	Specifies the time frame that the session cookie is valid. In this instance, the timer is set to expire after 600000 milliseconds, or 10 minutes, and initiate a logout event.
create_logout_request_url()	When the Service Provider session terminates, the Single Log Out (SLO) request URL created by this SAML2 library method is forwarded to the Identity Provider (IDP).
readFileSync()	Reads the key files and certificates synchronously, which is necessary for setting up the SAML2 Service Provider. For the Service Provider and Identity Provider to communicate securely, these certifications are necessary.
assert_endpoint	Indicates the URL that, following successful authentication, the Identity Provider will use to transmit the SAML assertion. By doing this, the Service Provider level of user authentication is guaranteed.
window.onload	This event is used to reset the session inactivity timer in the frontend. It makes sure that when the user loads the program for the first time, the timer starts over.
onmousemove	To reset the session timer, this event listener detects any mouse movement. It's essential for keeping an eye on user behavior and averting accidental session timeouts.
fetch()	Used to asynchronously send a SLO request, following the session timeout, to the server. In order to connect with the Identity Provider and log the user out of the IDP, it sets off the backend logic.
setTimeout()	This function in the frontend code causes the session timeout event to occur after the predetermined amount of inactivity. It is essential for keeping an eye on user behavior and implementing security regulations.

Optimizing Single Log Out with SAML 2.0 Session Timeout Handling

Using and Express, the backend script for handling Single Log Out (SLO) focuses on the capability to track user session expiration and initiate a logout sequence at the Service Provider (SP) and Identity Provider (IDP) levels. Management of Express sessions lies at the heart of this reasoning. We establish a trigger point by setting the session to terminate after a predetermined amount of inactivity—ten minutes, in our example. When the session ends, the script uses the `create_logout_request_url()} method to start a SAML 2.0 logout request, which then connects to the IDP (in this case, ) to end the user session entirely. This enhances security by guaranteeing that the user has completely logged out of the system.

We load and keys into the application using the `readFileSync()} command to enable secure communication between the SP (MyApp) and the IDP (Microsoft Entra). By authenticating the logout request, these certificates guard against illegal logouts and guarantee that the communication stays encrypted and confirmed. The user is sent to the logout request URL after it has been generated, where the IDP handles the logout and, if required, ends the user's session across any associated applications. Maintaining the security and integrity of multi-application Single Sign-On (SSO) installations requires this two-way communication.

The JavaScript script is essential for tracking user activities in real time on the front end. Every time the user interacts with the program, we reset the session timeout by using event listeners like as `onmousemove} and `onkeypress`. A timer that was set with `setTimeout()` alerts the user and automatically logs them out of the SP (MyApp) when the user becomes idle. Following logout, the SAML 2.0 logout process previously covered is started by the frontend script sending a SLO request to the backend using `fetch()`. This technique makes sure that inactivity at the SP level is addressed promptly, securely, and without fail.

When SAML 2.0 integration and are combined, the user experience is seamless and security standards are upheld. In order to prevent the user from staying authenticated for longer than is permitted during inactivity, the session timeout initiates both the local SP logout and the IDP logout. Although SAML 2.0 does not require any particular conduct in regards to session timeouts, it is generally accepted as a best practice to use session expiration to initiate SLO. By ending idle sessions, it strikes a balance between security and user experience by enabling synchronized logouts across various SSO-connected platforms.

// Required modules for Node.js and SAML SSO
const express = require('express');
const session = require('express-session');
const saml2 = require('saml2-js');
const app = express();

// Service Provider (SP) setup
const sp = new saml2.ServiceProvider({
  entity_id: "http://myapp.com/metadata.xml",
  private_key: fs.readFileSync("./cert/sp-private-key.pem").toString(),
  certificate: fs.readFileSync("./cert/sp-certificate.pem").toString(),
  assert_endpoint: "http://myapp.com/assert"
});

// Identity Provider (IDP) setup
const idp = new saml2.IdentityProvider({
  sso_login_url: "https://login.microsoftonline.com/sso",
  sso_logout_url: "https://login.microsoftonline.com/logout",
  certificates: fs.readFileSync("./cert/idp-certificate.pem").toString()
});

// Session management
app.use(session({
  secret: 'mySecretKey',
  resave: false,
  saveUninitialized: true,
  cookie: { maxAge: 600000 } // Set session expiration time
}));

// Middleware to handle session timeout and SLO
app.use((req, res, next) => {
  if (req.session.expires && Date.now() > req.session.expires) {
    sp.create_logout_request_url(idp, {}, (err, logout_url) => {
      if (err) return res.status(500).send("Logout error");
      return res.redirect(logout_url); // Trigger SLO
    });
  } else {
    next(); // Continue if session is valid
  }
});

app.listen(3000, () => {
  console.log("Server running on port 3000");
});

// Define variables for session timeout
let timeoutDuration = 600000; // 10 minutes
let timeoutTimer;

// Reset the timer on any user interaction
function resetTimer() {
  clearTimeout(timeoutTimer);
  timeoutTimer = setTimeout(triggerLogout, timeoutDuration);
}

// Trigger logout function
function triggerLogout() {
  alert("Session expired due to inactivity.");
  window.location.href = "/logout"; // Redirect to SP logout
}

// Monitor user actions
window.onload = resetTimer;
document.onmousemove = resetTimer;
document.onkeypress = resetTimer;

// SLO event triggered after logout
function sendSLORequest() {
  fetch('/api/slo', { method: 'POST' })
    .then(response => {
      if (response.ok) {
        console.log("SLO request sent to IDP");
      }
    })
    .catch(err => console.error("SLO request failed", err));
}

Exploring SAML 2.0: Single Log Out and Inactivity Timeout

How SAML 2.0 Single Log Out (SLO) addresses at the Service Provider (SP) level is a critical component to manage. Although it is obvious that a manual logout at the SP should cause an Identity Provider (IDP) logout as well, session timeouts brought on by inactivity complicate matters. The SAML 2.0 standard does not state clearly how SLO should be handled at session expirations. This does, however, allow for the adoption of best practices that can improve user experience and security.

For instance, even after being shut out of the SP due to inactivity, users who log into an application such as MyApp through Microsoft Entra (IDP) frequently stay logged into the IDP. If the user believes they are fully logged out while other apps utilizing the same SSO are still running, this could raise . Setting up SAML session management to mimic the SP timeout event at the IDP level and guarantee synchronized logouts is one way to reduce this risk.

The frontend code's implementation of idle detection techniques is another factor. Developers can anticipate times of inactivity and alert users before the session expires by using event listeners for user activity. By using this, users may keep control over their sessions and make sure that their doesn't run continuously. In an SSO-integrated environment, developers can preserve security and user comfort by striking a balance between these factors.

1. What occurs at the Service Provider level when a session times out?
2. Usually, the user is logged out of the program when a session times out at the SP level. It depends on how the system is set up, though, as the SAML 2.0 spec does not require that this cause a SLO at the IDP.
3. Should a SLO at the Identity Provider be triggered by a Service Provider session timeout?
4. The organization's policy governs this. Though SAML 2.0 does not mandate it, many choose to set off SLO at the IDP when the SP session ends for security reasons.
5. When an inactive session ends, how can I make SLO happen?
6. Session expiration can be detected via a backend mechanism, which then initiates a procedure to make a SLO request to the IDP.
7. How is session inactivity detected on the frontend?
8. Event listeners like as and are commonly used to track inactivity as they reset a timer each time a user interacts with the application.
9. After logging out of the SP, is it safe to have the IDP session open?
10. A security risk may arise from leaving the IDP session open, particularly if the user believes they have completely checked out. Setting up SLO to replicate SP session expiration is advised.

Maintaining security in an SSO system requires making sure that the Identity Provider and Service Provider synchronize their logout processes. Even though SAML 2.0 does not mandate how session timeouts should be handled, a lot of businesses handle single logouts in a uniform way.

It is advised to send a SLO request each time the Service Provider session ends because of inactivity in order to improve security. This ensures that the user has logged out of the Identity Provider as well as the application, avoiding unwanted access on many platforms.