Flexible Checkout Fields for WooCommerce <= 2.3.1 - Unauthenticated Arbitrary Plugin Settings Update
Strategic Overview
- Status
- Patched in 2.3.2
- Affected Version
< 2.3.2- CVSS
- 7.2High
- Weakness type
- CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- CVE
CVE-2020-36731
At a glance
CVE-2020-36731 is a high-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Flexible Checkout Fields for WooCommerce WordPress plugin, affecting versions < 2.3.2. It carries a CVSS score of 7.2 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 2.3.2; sites on affected versions should update now. Disclosed February 2020, reported by Jerome Bruandet.
Vulnerability Overview
The Flexible Checkout Fields for WooCommerce plugin for WordPress is vulnerable to Unauthenticated Arbitrary Plugin Settings update, in addition to Stored Cross-Site Scripting in versions up to, and including, 2.3.1. This is due to missing authorization checks on the updateSettingsAction() function which is called via an admin_init hook, along with missing sanitization and escaping on the settings that are stored.
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, and no interaction from a victim user.
CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Flexible Checkout Fields for WooCommerce < 2.3.2 carries this weakness at updateSettingsAction(), and reaching it takes no account at all. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.
Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For Flexible Checkout Fields for WooCommerce the fix is 2.3.2: builds < 2.3.2 are affected, anything from 2.3.2 onward is not.
Remediation
Update to version 2.3.2, or a newer patched version
How does WordSec protect against this?
Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Flexible Checkout Fields for WooCommerce 2.3.2 closes this, and updating the plugin is the step that ends it.
- Firewall
- Login Security
- Alerts
External References
Related records
Other vulnerabilities in Flexible Checkout Fields for WooCommerce – WooCommerce Checkout Manager
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