This article is a part of our Vulnerability Database (back to index)
Cross-site Scripting occurrences in Ext Js
The getTip() method of Action Columns of Sencha Ext JS 4 to 6 before 6.6.0 is vulnerable to XSS attacks, even when passed HTML-escaped data. This framework brings no built-in XSS protection, so the developer has to ensure that data is correctly sanitized. However, the getTip() method of Action Columns takes HTML-escaped data and un-escapes it. If the tooltip contains user-controlled data, an attacker could exploit this to create a cross-site scripting attack, even when developers took precautions and escaped data. (2018-07-05, CVE-2018-8046)
Why Cross-site Scripting can be dangerous
Cross site scripting is an attack where a web page executes code that is injected by an adversary. It usually appears, when users input is presented. This attack can be used to impersonate a user, take over control of the session, or even steal API keys.
The attack can be executed e.g. when you application injects the request parameter directly into the HTML code of the page returned to the user:
https://server.com/confirmation?message=Transaction+Complete
what results in:
<span>Confirmation: Transaction Complete</span>
In that case the message can be modified to become a valid Javascript code, e.g.:
https://server.com/confirmation?message=<script>dangerous javascript code here</script>
and it will be executed locally by the user's browser with full access to the user's personal application/browser data:
<span>Confirmation: <script>dangerous javascript code here</script></span>