CVE-2024-23756 is a high-severity vulnerability affecting the official Plone Docker image version 5.2.13 (build 5221). The core issue arises from the HTTP PUT and DELETE methods being enabled without authentication controls. These HTTP methods allow clients to upload or delete files on the server. Because they are enabled and accessible without any authentication or user interaction, unauthenticated attackers can exploit this to perform unauthorized file uploads or deletions. This can lead to significant integrity risks, such as overwriting or deleting critical files, potentially enabling further exploitation or denial of service conditions. The vulnerability is network exploitable (AV:N), requires no privileges (PR:N), no user interaction (UI:N), and affects the integrity of the system (I:H) without impacting confidentiality or availability. The scope is unchanged (S:U), meaning the vulnerability affects only the vulnerable component. Although no known exploits are reported in the wild yet, the ease of exploitation and the critical nature of file manipulation make this a serious threat. The lack of vendor or product-specific details beyond the Plone Docker image suggests the vulnerability is specific to this containerized deployment of Plone CMS version 5.2.13. Plone is an open-source content management system widely used in various organizations, including government and enterprises, for managing web content. The vulnerability could be leveraged to upload malicious web shells, deface websites, or delete important content, severely impacting the integrity of affected systems.

For European organizations using the Plone CMS via the official Docker image 5.2.13, this vulnerability poses a significant risk. Unauthorized file uploads could allow attackers to deploy web shells or malware, leading to persistent access, data manipulation, or lateral movement within networks. Deletion of files could disrupt web services, causing operational downtime and reputational damage. Given Plone's use in public sector websites, educational institutions, and enterprises across Europe, exploitation could impact critical information infrastructure and public-facing services. The integrity compromise could also undermine trust in digital services and lead to regulatory consequences under GDPR if personal data is indirectly affected through service disruption or manipulation. The vulnerability’s network accessibility and lack of authentication requirements increase the likelihood of automated scanning and exploitation attempts, especially in environments where Docker containers are exposed to the internet without adequate network segmentation or firewall protections.

Specific mitigation steps include: 1) Immediately disable the HTTP PUT and DELETE methods in the Plone Docker container configuration if they are not explicitly required. This can be done by adjusting the web server or application settings within the container to reject these methods. 2) If these methods are necessary for functionality, implement strict authentication and authorization controls to ensure only trusted users can perform PUT or DELETE requests. 3) Restrict network exposure of the Plone Docker container by placing it behind firewalls or reverse proxies that filter or block unsafe HTTP methods. 4) Regularly update the Plone Docker image to the latest patched version once available from the vendor or community, as this vulnerability is expected to be addressed in future releases. 5) Monitor web server logs for unusual PUT or DELETE requests and implement intrusion detection rules to alert on such activity. 6) Conduct thorough audits of deployed Plone containers to identify any unauthorized file changes or uploads. 7) Employ container security best practices, including minimal privileges for container processes and network segmentation to limit attacker movement if compromise occurs.