CVE-2020-36389

CiviCRM < 5.28.1 - Cross-Site Request Forgery to Cross-Site Scripting

2021-06-22 00:00

Strategic Overview

Status: Patched in 5.28.1
Affected Plugin: CiviCRM for WordPress
Affected Version: <= 5.28.0
CVSS: 6.1Medium
Weakness type: CWE-352 · Cross-Site Request Forgery (CSRF)
CVE: CVE-2020-36389

View all CiviCRM for WordPress vulnerabilities

At a glance

CVE-2020-36389 is a medium-severity Cross-Site Request Forgery (CSRF) vulnerability in the CiviCRM for WordPress WordPress plugin, affecting versions <= 5.28.0. It carries a CVSS score of 6.1 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 5.28.1; sites on affected versions should update now. Disclosed June 2021, reported by Dennis Brinkrolf (sonarsource).

Vulnerability Overview

The CiviCRM plugin for WordPress is vulnerable to Stored Cross-Site Scripting via improper CSRF checks in the CKEditor Configuration Form in versions up to, and including, 5.28.0 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

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)

Reaching this weakness in CiviCRM for WordPress <= 5.28.0 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 CiviCRM for WordPress the fix is 5.28.1: builds <= 5.28.0 are affected, anything from 5.28.1 onward is not.

Remediation

Update to version 5.28.1, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to CiviCRM for WordPress: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: CiviCRM for WordPress 5.28.1 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2020-36389 https://www.wordfence.com/threat-intel/vulnerabilities/id/82fe99af-f254-4f4f-ac27-3e1997c370f6 https://nvd.nist.gov/vuln/detail/CVE-2020-36389

CVSS Vector

6.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeChanged
ConfidentialityLow
IntegrityLow
AvailabilityNone

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