CVE-2021-24428 in RSS for Yandex Turbo Plugin
Summary
by MITRE • 08/02/2021
The RSS for Yandex Turbo WordPress plugin through 1.30 does not sanitise or escape some of its settings before saving and outputing them in the admin dashboard, leading to an Authenticated Stored Cross-Site Scripting issue even when the unfiltered_html capability is disallowed.
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Analysis
by VulDB Data Team • 08/06/2021
The vulnerability identified as CVE-2021-24428 affects the RSS for Yandex Turbo WordPress plugin version 1.30 and earlier, presenting a critical authenticated stored cross-site scripting flaw that undermines the security posture of affected WordPress installations. This issue stems from inadequate input sanitization and output escaping mechanisms within the plugin's administrative interface, creating a persistent security weakness that can be exploited by authenticated attackers with sufficient privileges to modify plugin settings.
The technical flaw manifests in the plugin's handling of user-supplied data within its settings management system. When administrators configure the RSS for Yandex Turbo plugin, certain input parameters are not properly sanitized before being stored in the WordPress database and subsequently rendered back in the admin dashboard interface. This failure to implement proper data validation and output escaping creates a condition where malicious scripts can be injected and persistently stored, executing whenever the affected admin pages are loaded. The vulnerability is particularly concerning because it operates even when the unfiltered_html capability is restricted, which typically prevents non-administrator users from injecting raw HTML content into WordPress posts and pages.
The operational impact of this authenticated stored XSS vulnerability extends beyond simple script execution, as it can enable attackers to escalate privileges, steal administrative sessions, or manipulate the WordPress administrative interface. An attacker with access to a user account possessing sufficient permissions to modify plugin settings can inject malicious JavaScript code that will execute in the context of other administrators who view the plugin's configuration pages. This persistent threat can lead to complete compromise of the WordPress installation, allowing unauthorized access to sensitive data, modification of content, or deployment of additional malware. The stored nature of the vulnerability means that the malicious payload remains active even after the initial injection, continuously affecting any administrator who accesses the compromised administrative interface.
Security professionals should consider this vulnerability in the context of CWE-79 which specifically addresses cross-site scripting flaws, and its alignment with ATT&CK technique T1059.007 for command and control using scripting. The vulnerability demonstrates poor input validation practices that violate fundamental security principles of defense in depth and least privilege. Organizations should immediately implement mitigations including updating to the patched version of the RSS for Yandex Turbo plugin, implementing proper access controls, and monitoring for suspicious administrative activities. Additionally, administrators should consider implementing web application firewalls to detect and prevent exploitation attempts, while conducting thorough security audits of all installed WordPress plugins to identify similar sanitization issues. The vulnerability highlights the critical importance of proper input validation and output escaping in web applications, particularly within administrative interfaces where privileged access exists.