CVE-2020-4048

WordPress Core < 5.4.2 - Open Redirect

2020-06-10 00:00
Ben Bidner

Strategic Overview

Status
Patched in 3.7.34
Affected Core
WordPress 5.3
Affected Version
3.7 – 5.3.3 · 18 branches
CVSS
5.7Medium
Weakness type
CWE-601 · URL Redirection to Untrusted Site ('Open Redirect')
CVE
CVE-2020-4048
View all WordPress 5.3 vulnerabilities

At a glance

CVE-2020-4048 is a medium-severity URL Redirection to Untrusted Site ('Open Redirect') vulnerability in the WordPress 5.3 WordPress release line, affecting 3.7 – 5.3.3 · 18 branches. It carries a CVSS score of 5.7 (reachable over the network; low attack complexity; high integrity impact). The issue is fixed in version 3.7.34; sites on affected versions should update now. Disclosed June 2020, reported by Ben Bidner.

Vulnerability Overview

In affected versions of WordPress, due to an issue in wp_validate_redirect() and URL sanitization, an arbitrary external link can be crafted leading to unintended/open redirect when clicked. This has been patched in version 5.4.2, along with all the previously affected versions via a minor release (5.3.4, 5.2.7, 5.1.6, 5.0.10, 4.9.15, 4.8.14, 4.7.18, 4.6.19, 4.5.22, 4.4.23, 4.3.24, 4.2.28, 4.1.31, 4.0.31, 3.9.32, 3.8.34, 3.7.34).

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed. A successful exploit has high impact on integrity.

CWE-601: URL Redirection to Untrusted Site ('Open Redirect')

WordPress 5.3 3.7 – 5.3.3 · 18 branches carries this weakness at wp_validate_redirect(), and reaching it takes a caller who can reach the endpoint. An open redirect is a page that takes a destination from the request and sends the browser there without checking that the destination belongs to the site.

A link that starts on a trusted domain finishes on an attacker's, which is what makes phishing and consent-screen abuse credible to the person clicking it. For WordPress 5.3 the fix is 3.7.34: builds 3.7 – 5.3.3 · 18 branches are affected, anything from 3.7.34 onward is not.

Remediation

Update to one of the following versions, or a newer patched version: 3.7.34, 3.8.34, 3.9.32, 4.0.31, 4.1.31, 4.2.28, 4.3.24, 4.4.23, 4.5.22, 4.6.19, 4.7.18, 4.8.14, 4.9.15, 5.0.10, 5.1.6, 5.2.7, 5.3.4, 5.4.2

How does WordSec protect against this?

The attempt arrives as an ordinary request to WordPress 5.3: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: updating to 3.7.34 is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2020-4048https://www.wordfence.com/threat-intel/vulnerabilities/id/bc6a8c0e-1136-41ff-bfc2-450434aa6326https://nvd.nist.gov/vuln/detail/CVE-2020-4048

Related records

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