Add support for InTune Single-Sign-On

This add support for communicating with the Microsoft Authentication Broker over its DBus interface in order to retrieve an authentication cookie, that can be used to automatically login the user currently logged-in via InTune. This also adds support for MFA and Conditional Access, which allows use of Teams outside of corporate network in case the organization has chosen to only allow access from registered devices. Behind the scene this uses the same mechanism as Microsoft Edge on Linux: upon loading a website from login.microsoftonline.com the URL is passed to the authentication broker in order to prepare a token based on the PRT (Primary Refresh Token). The returned refresh token is passed to the server via the 'X-Ms-Refreshtokencredential' HTTP header. With this token in place the server will skip any interactive prompts and generate a proper OAuth authentication token. Since the PRT is tied to the device credentials, the resulting refresh token carries the MFA attribute, which causes it to be accepted even if the Conditional Access policy mandates strong, device-based authentication. Signed-off-by: Krzysztof Nowicki <[email protected]>
IsmaelMartinez · Jun 3, 2024 · 5652a25 · 5652a25
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diff --git a/app/config/README.md b/app/config/README.md
@@ -57,6 +57,8 @@ Here is the list of available arguments and its usage:
 | spellCheckerLanguages           | Array of languages to use with Electron's spell checker                    | []                 |
 | ssoBasicAuthUser           | Login that will be sent for basic_auth SSO login. | string                 |
 | ssoBasicAuthPasswordCommand           | Command to execute, grab stdout and use it as a password for basic_auth SSO login. | string                 |
+| ssoIntuneEnabled                | Enable InTune Single-Sign-On                                                             | false
+| ssoIntuneAuthUser               | User (e-mail) to be used for InTune SSO login.                                           | string                 |
 | trayIconEnabled				 | Enable tray icon                                                                          | true               |
 | url                             | Microsoft Teams URL                                                                      | string                |
 | useMutationTitleLogic         | Use MutationObserver to update counter from title                                          | true               |

diff --git a/app/config/index.js b/app/config/index.js
@@ -275,6 +275,16 @@ function argv(configPath, appVersion) {
 				describe: 'Command to execute to retrieve password for SSO basic auth.',
 				type: 'string'
 			},
+			ssoInTuneEnabled: {
+				default: false,
+				describe: 'Enable Single-Sign-On using Microsoft InTune.',
+				type: 'boolean'
+			},
+			ssoInTuneAuthUser: {
+				default: '',
+				describe: 'User (e-mail) to use for InTune SSO.',
+				type: 'string'
+			},
 			trayIconEnabled: {
 				default: true,
 				describe: 'Enable tray icon',

diff --git a/app/intune/index.js b/app/intune/index.js
@@ -0,0 +1,91 @@
+const dbus = require('dbus-native');
+const { LucidLog } = require('lucid-log');
+
+var sessionBus = dbus.sessionBus();
+
+var intuneAccount = null;
+
+var brokerService = sessionBus.getService('com.microsoft.identity.broker1');
+
+function processInTuneAccounts(logger, resp, ssoInTuneAuthUser) {
+	response = JSON.parse(resp);
+	if ('error' in response) {
+		logger.warn('Failed to retrieve InTune account list: ' + response.error.context);
+		return;
+	};
+
+	if (ssoInTuneAuthUser == '') {
+		intuneAccount = response.accounts[0];
+		logger.debug('Using first available InTune account (' + intuneAccount.username + ')');
+	} else {
+		for (account in response.accounts) {
+			if (account.username == ssoIntuneAuthUser) {
+				intuneAccount = account;
+				logger.debug('Found matching InTune account (' + intuneAccount.username + ')');
+				break;
+			}
+		}
+		if (intuneAccount == null) {
+			logger.warn('Failed to find matching InTune account for ' + ssoIntuneAuthUser + '.');
+		}
+	}
+}
+
+exports.initSso = function initIntuneSso(logger, ssoInTuneAuthUser) {
+	logger.debug("Initializing InTune SSO");
+	brokerService.getInterface(
+		'/com/microsoft/identity/broker1',
+		'com.microsoft.identity.Broker1', function(err, broker) {
+			if (err) {
+				logger.warn('Failed to find microsoft-identity-broker DBus interface');
+				return;
+			}
+			broker.getAccounts('0.0', '', JSON.stringify({'clientId': '88200948-af09-45a1-9c03-53cdcc75c183', 'redirectUri':'urn:ietf:oob'}), function(err, resp) {
+				if (err) {
+					logger.warn('Failed to communicate with microsoft-identity-broker');
+					return;
+				}
+				processInTuneAccounts(logger, resp, ssoInTuneAuthUser);
+			});
+		});
+}
+
+exports.setupUrlFilter = function setupUrlFilter(filter) {
+	filter.urls.push('https://login.microsoftonline.com/*');
+}
+
+exports.isSsoUrl = function isSsoUrl(url) {
+	return intuneAccount != null && url.startsWith('https://login.microsoftonline.com/');
+}
+
+function processPrtResponse(logger, resp, detail) {
+	response = JSON.parse(resp);
+	if ('error' in response) {
+		logger.warn('Failed to retrieve Intune SSO cookie: ' + response.error.context);
+	} else {
+		logger.debug('Adding SSO credential');
+		detail.requestHeaders['X-Ms-Refreshtokencredential'] = response['cookieContent'];
+	}
+}
+
+exports.addSsoCookie = function addIntuneSsoCookie(logger, detail, callback) {
+	logger.debug('Retrieving InTune SSO cookie');
+	if (intuneAccount == null) {
+		logger.info("InTune SSO not active");
+		callback({
+			requestHeaders: detail.requestHeaders
+		});
+		return;
+	}
+	brokerService.getInterface(
+		'/com/microsoft/identity/broker1',
+		'com.microsoft.identity.Broker1', function(err, broker) {
+			broker.acquirePrtSsoCookie('0.0', '', JSON.stringify({'ssoUrl':detail.url, 'account':intuneAccount, 'authParameters':{'authority':'https://login.microsoftonline.com/common/'}}), function(err, resp) {
+				processPrtResponse(logger, resp, detail);
+				callback({
+					requestHeaders: detail.requestHeaders
+				});
+			});
+		});
+}
+
diff --git a/app/mainAppWindow/index.js b/app/mainAppWindow/index.js
@@ -16,6 +16,7 @@ const TrayIconChooser = require('../browser/tools/trayIconChooser');
 const { AppConfiguration } = require('../appConfiguration');
 const connMgr = require('../connectionManager');
 const fs = require('fs');
+const intune = require('../intune');
 
 /**
  * @type {TrayIconChooser}
@@ -65,6 +66,10 @@ exports.onAppReady = async function onAppReady(configGroup) {
 		levels: config.appLogLevels.split(',')
 	});
 
+	if (config.ssoInTuneEnabled) {
+		intune.initSso(logger, config.ssoInTuneAuthUser);
+	}
+
 	window = await createWindow();
 
 	if (config.trayIconEnabled) {
@@ -323,12 +328,16 @@ function setImgSrcSecurityPolicy(policies) {
  * @param {Electron.BeforeSendResponse} callback
  */
 function onBeforeSendHeadersHandler(detail, callback) {
-	if (detail.url.startsWith(customBGServiceUrl.href)) {
-		detail.requestHeaders['Access-Control-Allow-Origin'] = '*';
+	if (intune.isSsoUrl(detail.url)) {
+		intune.addSsoCookie(logger, detail, callback);
+	} else {
+		if (detail.url.startsWith(customBGServiceUrl.href)) {
+			detail.requestHeaders['Access-Control-Allow-Origin'] = '*';
+		}
+		callback({
+			requestHeaders: detail.requestHeaders
+		});
 	}
-	callback({
-		requestHeaders: detail.requestHeaders
-	});
 }
 
 /**
@@ -409,6 +418,7 @@ function addEventHandlers() {
 
 function getWebRequestFilterFromURL() {
 	const filter = customBGServiceUrl.protocol === 'http:' ? { urls: ['http://*/*'] } : { urls: ['https://*/*'] };
+	intune.setupUrlFilter(filter);
 	return filter;
 }
 

diff --git a/package.json b/package.json
@@ -40,6 +40,7 @@
     "release": "electron-builder"
   },
   "dependencies": {
+    "dbus-native": "0.4.0",
     "@electron/remote": "^2.1.2",
     "electron-is-dev": "2.0.0",
     "electron-store": "8.2.0",