A cross-site scripting (XSS) attack can cause arbitrary code (JavaScript) to run in a userโs browser while the browser is connected to a trusted web site. The application targets yourย users and not the application itself, but it uses your application as the vehicle for the attack. XSS payload was executed when the user loads a malicious link generated using the ajax call back in Greenmart autocomplete search.
Securin Zero-Days
CVE-2020-16140 – Reflected Cross-Site Scripting in Thembay
Severity:High
Vendor
Thembay
Affected Product
Greenmart version 2.4.2.
CVE
CVE-2020-16140
Securin ID
2020-CSW-07-1045
Status
Fixed
Date
July 17, 2020
Description
Proof of Concept (POC):
The following vulnerability was tested on the Greenmart theme on WordPress with version 5.4.2.
Issue 01: Reflected cross-site scripting.
- Install the Greenmart theme on WordPress with version 5.4.2.
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Figure-01: The view-source of the WordPress application, which confirms the theme is Greenmart.
Figure-02: Greenmart search functionality
Figure-03: The search action related backend ajax call
Figure-04: The ajax call to โgreenmart_autocomplete_searchโ action and the response from the server
Figure-05: Call-back request parameter with payload and the response from the server.
2. Click on the following link http://localhost/wordpress/wp-admin/admin-ajax.php?callback=–>%27″><svg/onload=alert(document.cookie)>&action=greenmart_autocomplete_search&term=defaultText&_=1593737670196
Figure-06: The call-back parameter is vulnerable to Reflected XSS, and itโs getting executed in the user browser context.
Figure-07: Wp-config configuration related to protecting XSS.
Impact
When the user input from a URL or POST data is reflected on the page without being stored, thus allowing the attacker to inject malicious content. This means that an attacker has to send a crafted malicious URL or post form to the victim to insert the payload.
Remediations
Download and apply the relevant patches from the vendor:
Timeline
July 17, 2020:ย Reported to Vendor
July 17, 2020: Vendor Responded
July 18, 2020: Vendor Released Fixed
July 29, 2020: CVE Assigned