Trustwave SpiderLabs Security Advisory TWSL2021-016:
Stored XSS in WordPress Plugin Timetable and Event Schedule by MotoPress

Published: 09/10/2021 
Version: 1.1

Vendor: MotoPress ( https://motopress.com/ )
Product: WordPress Plugin Timetable and Event Schedule by MotoPress
Version affected:  <= 2.3.18

Product description:
The plugin is an organizer plugin for creating and managing event schedules

Finding 1: Multiple Stored XSS
*****Credit: Martin Vierula of Trustwave
CVE: CVE-2021-24724
CWE: CWE-79

Multiple parameters are vulnerable to stored Cross-site Scripting.

Although authentication is required to exploit these, user roles lower than
admin (such as author) have the required permissions.

Parameters confirmed to be vulnerable:
 - The title of the event
 - Event Subtitle
 - Column names
 - Custom Event URL
 - Description field of 'Add New / Edit Timeslot'

PoCs for three of the five are provided below.  They can all be directly entered
into input fields in the browser.

PoC for 'Event Subtitle":
Random Event Subtitle1<script>alert(1);</script>

PoC for 'Custom Event URL':
http://localhost/wp/myevent.html" onclick="alert(2)
[click through the event to the column's page, then click on the link]

PoC for 'Description' field of 'Add New / Edit Timeslot'
My timeslot description</span><script>alert(3);</script>

Remediation Steps:
Upgrade the WordPress Plugin Timetable and Event Schedule to 2.3.19 or the
latest stable version.

Revision History:
05/03/2021 - Attempt to contact vendor
07/01/2021 - Attempt to contact vendor
07/16/2021 - Vulnerability disclosed to plugins@wordpress.org
07/27/2021 - Patch released by vendor
08/31/2021 - Advisory version 1.0 published
09/10/2021 - CVE assigned
09/10/2021 - Advisory version 1.1 published


References
1. https://en-ca.wordpress.org/plugins/mp-timetable/#developers
2. https://wpscan.com/vulnerability/c1194a1e-bf33-4f3f-a4a6-27b76b1b1eeb


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About Trustwave SpiderLabs:
SpiderLabs(R) is the advanced security team at Trustwave focused on
application security, incident response, penetration testing, physical
security and security research. The team has performed over a thousand
incident investigations, thousands of penetration tests and hundreds of
application security tests globally. In addition, the SpiderLabs Research
team provides intelligence through bleeding-edge research and proof of
concept tool development to enhance Trustwave's products and services.
https://www.trustwave.com/spiderlabs

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