WordPress Sites Affected by Bugs in Gutenberg Template Library and Redux Framework

 

The Gutenberg Template Library & Redux Framework plugin for WordPress, which is deployed on over 1 million websites, has two vulnerabilities. According to the researchers, these might enable arbitrary plugin installation, post deletions, and access to potentially sensitive information about a site's configuration. Redux.io's plugin provides a variety of templates and building blocks for developing web pages in WordPress' Gutenberg editor. 

This plugin is a collection of WordPress Gutenberg blocks that allow publishers to quickly create websites using pre-built “blocks” while utilizing the Gutenberg interface. 

The first vulnerability (CVE-2021-38312) is rated as high-severity on the CVSS scale, with a score of 7.1 out of 10. It's caused by the plugin's use of the WordPress REST API, which handles requests to install and manage blocks. According to Wordfence, it fails to properly allow user permissions. 

The WordPress REST API allows apps to communicate with the user's WordPress site by sending and receiving data in JSON (JavaScript Object Notation) objects. It's the backbone of the WordPress Block Editor, and it may also help the user's theme, plugin, or custom app create new, more sophisticated interfaces for managing and publishing the user's site's content. 

“While the REST API Endpoints registered under the redux/v1/templates/ REST Route used a permission_callback to verify a user’s permissions, this call-back only checked whether or not the user sending the request had the edit_posts capability,” Wordfence researchers said in a Wednesday posting. Users with lower rights, such as contributors and authors, may utilize the redux/v1/templates/plugin-install endpoint to install any plugin from the WordPress repository, or the redux/v1/templates/delete_saved_block endpoint to delete posts, according to the researchers. 

The second vulnerability, a medium-severity flaw (CVE-2021-38314), has a CVSS score of 5.3. It exists because the Gutenberg Template Library & Redux Framework plugin registers numerous AJAX actions that are available to unauthenticated users, one of which is deterministic and predictable, allowing for the discovery of a site's $support_hash. 

“This $support_hash AJAX action, which was also available to unauthenticated users, called the support_args function in redux-core/inc/classes/class-redux-helpers.php, which returned potentially sensitive information such as the PHP version, active plugins on the site and their versions, and an unsalted md5 hash of the site’s AUTH_KEY and SECURE_AUTH_KEY,” according to Wordfence. An attacker may use the information to plot a website takeover using other vulnerable plugins, according to the researchers.