WordPress Footnotes Block Cross-Site Scripting Scanner

WordPress is widely utilized for creating and managing websites and blogs. Its flexibility and extensive plugin architecture make it a popular choice for developers and site administrators alike. The software allows for custom theming and extensible functionality through its robust plugin system. The Footnotes Block is an integral component that enhances content presentation by allowing inline footnotes. This feature is specifically useful for educational, academic, and detailed informational posts. Thus, WordPress caters to a broad spectrum of websites, from personal blogs to corporate e-commerce websites.

Cross-Site Scripting (XSS) vulnerabilities allow attackers to inject malicious scripts into web pages viewed by other users. In the context of the WordPress Footnotes Block, this vulnerability arises when certain options in the Footnotes block are not correctly escaped before rendering in a post or page. This oversight makes it feasible for individuals with the contributor role or higher to embed harmful scripts. Such scripts might be executed in a viewer’s browser session, causing unauthorized actions or stealing sensitive information. The consistent issue resides in improper input handling and escaping that web applications frequently encounter.

The vulnerability primarily concerns the handling of the 'footnotes' meta element within WordPress posts. When this element contains suspicious input, such as a script tag, it is not sufficiently sanitized. This specifically allows a contributor to craft a Footnotes Block that executes JavaScript in another user's browser session. The exploit involves posting malicious content in the meta field that stores footnotes. The script then gets executed once a visitor navigates to the compromised page or post, provided the malicious input is not appropriately contained.

While a successful attack using this vulnerability can have medium severity impact, it can nevertheless compromise affected sites significantly. An attacker can potentially hijack user sessions, deface web pages, or harvest user information, leading to broader privacy and security breaches. Sites with high traffic are especially at risk, as the vulnerability could affect numerous visitors quickly if exploited. Additional risks include loss of trust from users and potential legal implications due to privacy violations.

REFERENCES

• https://www.wordfence.com/threat-intel/vulnerabilities/wordpress-core/wordpress-core-63-631-authenticatedcontributor-cross-site-scripting-via-footnotes-block?asset_slug=wordpress
• https://wpscan.com/vulnerability/63270b61-dddd-4cc0-a091-a04cb4f682ec/