Classic Editor Addon < 2.6.4 - Cross-Site Request Forgery

2022-01-24 00:00
Jan w Oleju

Strategic Overview

Status
Patched in 2.6.4
Affected Plugin
Classic Editor +
Affected Version
<= 2.6.3
CVSS
8.8High
Weakness type
CWE-352 · Cross-Site Request Forgery (CSRF)
CVE
CVE pending
View all Classic Editor + vulnerabilities

At a glance

This record tracks a high-severity Cross-Site Request Forgery (CSRF) vulnerability in the Classic Editor + WordPress plugin, affecting versions <= 2.6.3. It carries a CVSS score of 8.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 2.6.4; sites on affected versions should update now. Disclosed January 2022, reported by Jan w Oleju.

Vulnerability Overview

The Classic Editor Addon plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 2.6.3. This is due to inclusion of a vulnerable version of the wp-dependency-installer library. This makes it possible for unauthenticated attackers to install and activate arbitrary plugins 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. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

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

Reaching this weakness in Classic Editor + <= 2.6.3 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 Classic Editor + the fix is 2.6.4: builds <= 2.6.3 are affected, anything from 2.6.4 onward is not.

Remediation

Update to version 2.6.4, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Classic Editor +: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Classic Editor + 2.6.4 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

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