Defiant has raised alarms about two significant vulnerabilities affecting CleanTalk’s anti-spam WordPress plugin, which could enable attackers to execute arbitrary code remotely without requiring authentication. These vulnerabilities, tracked as CVE-2024-10542 and CVE-2024-10781, are classified with a high severity score of 9.8 on the CVSS scale. They impact the “Spam protection, Anti-Spam, FireWall by CleanTalk” plugin, which boasts over 200,000 active installations on WordPress sites globally.
The flaws pose a significant risk by allowing remote attackers to install and activate arbitrary plugins, including potentially vulnerable ones that can then be exploited for remote code execution (RCE). According to Defiant, the first vulnerability, CVE-2024-10542, involves an authorization bypass issue. This weakness exists in a function responsible for handling remote calls and plugin installations, where token-based authorization is used to secure these actions.
However, two related functions intended to verify the originating IP address and domain name are vulnerable to exploitation. Attackers can manipulate these checks through IP and DNS spoofing, enabling them to specify an IP address or subdomain under their control. This bypasses the plugin’s authorization process, allowing the attacker to carry out actions such as installing, activating, deactivating, or uninstalling plugins without proper permissions.
The vulnerability was discovered in late October and was addressed with the release of version 6.44 of the plugin on November 1.
However, this update inadvertently introduced another vulnerability, CVE-2024-10781, which provided attackers with an alternative method of bypassing token authorization.
CVE-2024-10781 arises from a flaw in how the plugin processes tokens for authorization. Specifically, if a website has not configured an API key in the plugin, attackers can use a token that matches an empty hash value to authenticate themselves. This effectively nullifies the intended security measures and allows attackers to install and activate arbitrary plugins, which can then be exploited for malicious purposes, such as executing remote code.
The CleanTalk development team addressed this second vulnerability with the release of version 6.45 on November 14, which contains fixes for both CVE-2024-10542 and CVE-2024-10781. Despite the availability of this updated version, data from WordPress indicates that as of November 26, approximately half of the plugin’s active installations are still running outdated and vulnerable versions. This exposes a significant number of websites to potential exploitation.
The risks associated with these vulnerabilities are considerable, as attackers could gain complete control over affected websites by leveraging these flaws. This includes the ability to install additional plugins, some of which may themselves contain vulnerabilities that could be exploited for further malicious activities.
Website administrators using the CleanTalk anti-spam plugin are strongly urged to update to version 6.45 or later as soon as possible. Keeping plugins up to date is a critical step in maintaining the security of WordPress websites. By applying the latest updates, administrators can protect their sites against known vulnerabilities and reduce the risk of being targeted by cyberattacks.
In addition to updating plugins, security experts recommend implementing additional security measures, such as monitoring for unauthorized changes, using a robust firewall, and conducting regular security audits.
These practices can help ensure that websites remain secure against evolving threats.
By addressing these vulnerabilities and staying proactive about updates, WordPress site owners can safeguard their online presence and protect the sensitive data entrusted to their platforms.