A security vulnerability exists in Update Rollup 13 for Windows Azure Pack (WAP) that causes script injection of certain symbols to bypass portal UI restrictions. The portal UI restricts certain symbols such as greater than ( < ) and less than ( > ) symbols that are needed for “<script>” injection.
By replaying a request in Fiddler, strings that contain characters such as < and > can be sent as the subscription name. The SubscriptionName field can be set to any string up to 128 characters. In this scenario, you can load and run various scripts such as <script src="https://code.jquery.com/jquery-1.10.2.min.js"> or <script>alert(document.cookie)</script>.
To learn more about this vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2018-8652.