CVE-2021-24193 in Visitor Traffic Real Time Statistics Plugin
Summary
by MITRE • 05/14/2021
Low privileged users can use the AJAX action 'cp_plugins_do_button_job_later_callback' in the Visitor Traffic Real Time Statistics WordPress plugin before 2.12, to install any plugin (including a specific version) from the WordPress repository, as well as activate arbitrary plugin from then blog, which helps attackers install vulnerable plugins and could lead to more critical vulnerabilities like RCE.
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Analysis
by VulDB Data Team • 05/16/2021
The vulnerability identified as CVE-2021-24193 represents a critical authorization flaw within the Visitor Traffic Real Time Statistics WordPress plugin, affecting versions prior to 2.12. This issue stems from insufficient access controls on the AJAX endpoint cp_plugins_do_button_job_later_callback, which allows low-privileged users to execute administrative functions without proper authentication. The vulnerability falls under CWE-284, which specifically addresses improper access control mechanisms, and aligns with ATT&CK technique T1068, which covers exploit for privilege escalation through the manipulation of application logic. The flaw enables attackers to bypass standard WordPress user permission systems and perform actions typically restricted to administrators or editors.
The technical implementation of this vulnerability exploits the plugin's lack of proper nonce validation and user role verification within the AJAX callback handler. When a user submits a request to the cp_plugins_do_button_job_later_callback endpoint, the plugin fails to verify whether the requesting user possesses sufficient privileges to install or activate plugins. This oversight creates a direct pathway for privilege escalation, as the AJAX action accepts parameters that specify plugin names and versions from the WordPress repository, effectively allowing any authenticated user to download and install arbitrary plugins. The vulnerability is particularly dangerous because it operates within the WordPress admin interface context, leveraging legitimate plugin functionality to execute malicious code.
The operational impact of CVE-2021-24193 extends far beyond simple privilege escalation, as it provides attackers with the ability to install potentially malicious plugins from the WordPress repository. This capability creates a significant attack surface since plugins are trusted components that often have elevated permissions and access to sensitive system functions. Attackers can exploit this vulnerability to install plugins with known vulnerabilities, potentially leading to remote code execution or complete system compromise. The ability to specify exact plugin versions allows for precise exploitation of known vulnerabilities in specific plugin versions, making this attack vector particularly effective against systems running outdated or vulnerable plugins.
Mitigation strategies for CVE-2021-24193 focus on immediate plugin updates to version 2.12 or later, which includes proper access control measures and nonce validation. Administrators should also implement additional security layers including regular security audits of installed plugins, monitoring for unauthorized plugin installations, and restricting user privileges to the minimum required for their roles. The WordPress security team recommends that all users update immediately and that organizations implement automated patch management systems to prevent such vulnerabilities from being exploited. Organizations should also consider implementing web application firewalls and monitoring for suspicious AJAX requests that attempt to manipulate plugin installation parameters, as these activities represent common exploitation patterns associated with this type of vulnerability.