The Pluck CMS 4.7.7-dev2 version suffers from a critical PHP code execution vulnerability identified as CVE-2018-11736. This vulnerability stems from insufficient validation of file uploads in the 'Manage Images' section of the admin panel. An attacker with authenticated access can upload a .htaccess file with a content-type of 'image/jpeg' containing Apache directives like 'AddType application/x-httpd-php .jpg'. This configuration causes the Apache web server to interpret .jpg files as PHP scripts, enabling execution of arbitrary PHP code embedded within these files. The exploit leverages the Apache AllowOverride feature, commonly enabled in shared hosting environments, which permits .htaccess files to override server configurations. The attacker uploads a crafted .htaccess file and a malicious .jpg file containing PHP code. When the .jpg file is accessed via a browser, the embedded PHP code executes, granting the attacker full control over the server environment. The vulnerability requires authentication, but credential compromise can occur through phishing, weak passwords, or credential theft. The exploit has been tested on both Ubuntu and Windows platforms, demonstrating cross-platform applicability. No official patches or updates are currently available, so organizations must implement mitigations proactively. Potential consequences include server compromise, data exfiltration, website defacement, and lateral movement within internal networks. The root cause is a combination of insufficient file upload validation and permissive server configurations allowing .htaccess overrides in image directories.

For European organizations, this vulnerability poses a significant threat to web servers running Pluck CMS, especially those hosting sensitive or critical content. Exploitation can lead to unauthorized access, data breaches, website defacement, and lateral movement within corporate networks. Sectors such as education, media, small and medium enterprises, and government agencies using Pluck CMS may experience service disruption and reputational damage. The ability to execute arbitrary PHP code enables attackers to install backdoors, exfiltrate sensitive data, or launch further attacks against internal systems. Since exploitation requires admin credentials, the risk is heightened if credential hygiene is poor or if phishing/social engineering attacks succeed. The vulnerability could also be used to bypass security controls and evade detection. Although rated medium severity, the actual impact could be critical in targeted attacks. European data protection regulations like GDPR impose strict data security requirements, so breaches caused by this vulnerability could result in regulatory penalties and legal consequences. The threat is particularly acute in countries with higher Pluck CMS usage and where attackers focus on web infrastructure as an attack vector.

1. Restrict access to the Pluck CMS admin panel using IP whitelisting, VPNs, or multi-factor authentication to reduce the risk of credential compromise. 2. Disable Apache's AllowOverride directive or configure the web server to ignore .htaccess files in image upload directories to prevent malicious overrides. 3. Implement strict file upload validation to block uploads of .htaccess files or files with executable content types disguised as images. 4. Regularly audit and monitor uploaded files for suspicious content or unauthorized changes, especially in web-accessible directories. 5. Apply the latest security patches or upgrade to a Pluck CMS version that addresses this vulnerability if available. 6. Conduct regular credential audits and enforce strong password policies for admin accounts. 7. Deploy web application firewalls (WAFs) with rules to detect and block attempts to upload or access malicious files. 8. Monitor web server logs for unusual requests to .jpg files or .htaccess uploads. 9. Educate administrators about phishing and social engineering risks to protect admin credentials. 10. Consider isolating the CMS environment to limit potential damage from a compromised server.