CVE-2020-36754

Paid Memberships Pro <= 2.4.2 - Cross-Site Request Forgery Bypass

2020-09-16 00:00
Jerome Bruandet

Strategic Overview

Status
Patched in 2.4.3
Affected Plugin
Paid Memberships Pro – Content Restriction, User Registration, & Paid Subscriptions
Affected Version
< 2.4.3
CVSS
4.3Medium
Weakness type
CWE-352 · Cross-Site Request Forgery (CSRF)
CVE
CVE-2020-36754
View all Paid Memberships Pro – Content Restriction, User Registration, & Paid Subscriptions vulnerabilities

At a glance

CVE-2020-36754 is a medium-severity Cross-Site Request Forgery (CSRF) vulnerability in the Paid Memberships Pro WordPress plugin, affecting versions < 2.4.3. 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 2.4.3; sites on affected versions should update now. Disclosed September 2020, reported by Jerome Bruandet.

Vulnerability Overview

The Paid Memberships Pro plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 2.4.2. This is due to missing or incorrect nonce validation on the pmpro_page_save() function. This makes it possible for unauthenticated attackers to save pages 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)

Paid Memberships Pro < 2.4.3 carries this weakness at pmpro_page_save(), 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 Paid Memberships Pro the fix is 2.4.3: builds < 2.4.3 are affected, anything from 2.4.3 onward is not.

Remediation

Update to version 2.4.3, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Paid Memberships Pro: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Paid Memberships Pro 2.4.3 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2020-36754https://www.wordfence.com/threat-intel/vulnerabilities/id/d74553a4-0ef7-4908-a2e8-5e0216f7b256https://nvd.nist.gov/vuln/detail/CVE-2020-36754

Related records

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