This article is a part of our Vulnerability Database (back to index)
Cross-site Scripting occurrences in Documents
An issue was discovered in the Readdle Documents app before 6.9.7 for iOS. The application's file-transfer web server improperly displays directory names, leading to Stored XSS, which may be used to steal a user's data. This requires user interaction because there is no known direct way for an attacker to create a crafted directory name on a victim's device. However, a crafted directory name can occur if a victim extracts a ZIP archive that was provided by an attacker. (2020-05-18, CVE-2019-20802)
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>