CVE-2021-4399

Edwiser Bridge <= 2.0.6 - Cross-Site Request Forgery Bypass

2021-06-28 00:00
Jerome Bruandet

Strategic Overview

Status
Patched in 2.0.7
Affected Plugin
Edwiser Bridge – WordPress Moodle Integration
Affected Version
<= 2.0.6
CVSS
4.3Medium
Weakness type
CWE-352 · Cross-Site Request Forgery (CSRF)
CVE
CVE-2021-4399
View all Edwiser Bridge – WordPress Moodle Integration vulnerabilities

At a glance

CVE-2021-4399 is a medium-severity Cross-Site Request Forgery (CSRF) vulnerability in the Edwiser Bridge WordPress plugin, affecting versions <= 2.0.6. It carries a CVSS score of 4.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 2.0.7; sites on affected versions should update now. Disclosed June 2021, reported by Jerome Bruandet.

Vulnerability Overview

The Edwiser Bridge plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including,2.0.6. This is due to missing or incorrect nonce validation on the user_data_synchronization_initiater(), course_synchronization_initiater(), users_link_to_moodle_synchronization(), connection_test_initiater(), admin_menus(), and subscribe_handler() function. This makes it possible for unauthenticated attackers to perform unauthorized actions via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site.

CWE-352: Cross-Site Request Forgery (CSRF)

Edwiser Bridge <= 2.0.6 carries this weakness at user_data_synchronization_initiater(), and reaching it takes a caller who can reach the endpoint. Cross-site request forgery abuses the fact that browsers attach a victim's cookies to any request, so a state-changing action that only checks who you are, not whether you meant to act, can be triggered from another site.

An attacker who gets a logged-in user to load a crafted page can perform that action as them, with the impact scaling to whatever the victim's role is allowed to do. For Edwiser Bridge the fix is 2.0.7: builds <= 2.0.6 are affected, anything from 2.0.7 onward is not.

Remediation

Update to version 2.0.7, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Edwiser Bridge: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Edwiser Bridge 2.0.7 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-4399https://www.wordfence.com/threat-intel/vulnerabilities/id/6450dafd-5992-4831-87af-e5e47cc8663ehttps://nvd.nist.gov/vuln/detail/CVE-2021-4399

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C