CVE-2021-24277 in RSS for Yandex Turbo Plugin
Summary
by MITRE • 05/14/2021
The RSS for Yandex Turbo WordPress plugin before 1.30 did not properly sanitise the user inputs from its Счетчики settings tab before outputting them back in the page, leading to authenticated stored Cross-Site Scripting issues
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Analysis
by VulDB Data Team • 05/16/2021
The vulnerability identified as CVE-2021-24277 affects the RSS for Yandex Turbo WordPress plugin version 1.30 and earlier, representing a critical security flaw that enables authenticated stored cross-site scripting attacks. This issue stems from insufficient input sanitization within the plugin's administration interface, specifically within the settings tab where user-provided data is processed and subsequently rendered back to users without proper validation or escaping mechanisms. The vulnerability occurs when administrators or authenticated users interact with the plugin's configuration interface, creating a persistent XSS vector that can be exploited by attackers who have gained access to legitimate user accounts.
The technical root cause of this vulnerability aligns with CWE-79, which describes improper neutralization of input during web page generation, specifically manifesting as stored cross-site scripting. The flaw exists because the plugin fails to implement proper output escaping or sanitization routines when processing user inputs from the settings tab. When administrators save configuration data through the web interface, the plugin stores this information without adequate sanitization before displaying it back to users, creating an environment where malicious scripts can be injected and persistently executed. This stored XSS vulnerability allows attackers to inject malicious JavaScript code that executes in the context of other users' browsers, potentially leading to session hijacking, data theft, or further compromise of the affected WordPress installation.
The operational impact of CVE-2021-24277 extends beyond simple script execution, as it can enable attackers to escalate privileges and compromise entire WordPress installations. An authenticated attacker with access to the plugin's settings interface can inject malicious payloads that persistently execute whenever other users view the affected pages, potentially affecting multiple users within the same organization. This vulnerability can be particularly dangerous in multi-user environments where administrators might inadvertently execute malicious scripts when reviewing plugin settings or configuration pages. The stored nature of the XSS means that the attack vector remains active until the malicious content is removed from the database, making it difficult to detect and remediate without thorough database inspection and cleaning.
Mitigation strategies for this vulnerability should include immediate plugin updates to version 1.30 or later, which contain the necessary sanitization fixes. System administrators should also implement additional defensive measures such as input validation at multiple layers, proper output escaping for all user-generated content, and regular security auditing of WordPress plugins. The ATT&CK framework categorizes this vulnerability under T1548.003 for abuse of alternate authentication material, as it leverages legitimate administrative access to establish persistent malicious presence within the WordPress environment. Organizations should also consider implementing content security policies to limit the impact of potential XSS attacks, along with regular monitoring of plugin configurations and user access logs to detect anomalous activities that might indicate exploitation attempts.