CVE-2016-9268 in DotClear
Summary
by MITRE
Unrestricted file upload vulnerability in the Blog appearance in the "Install or upgrade manually" module in Dotclear through 2.10.4 allows remote authenticated super-administrators to execute arbitrary code by uploading a theme file with an zip extension, and then accessing it via unspecified vectors.
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Analysis
by VulDB Data Team • 10/03/2022
The CVE-2016-9268 vulnerability represents a critical security flaw in the Dotclear content management system affecting versions through 2.10.4. This vulnerability exists within the Blog appearance module's "Install or upgrade manually" functionality, where the system fails to properly validate file uploads. The flaw specifically targets the theme installation process, creating an avenue for remote code execution through improper file handling mechanisms. The vulnerability is particularly dangerous because it requires only authenticated access as a super administrator, making it exploitable by users with elevated privileges who can leverage this weakness to compromise the entire system.
The technical implementation of this vulnerability stems from inadequate input validation and file extension handling within the upload mechanism. When administrators upload theme files with zip extensions, the system does not properly verify the contents or enforce strict file type restrictions. This allows malicious actors to upload zip archives containing malicious code that can be executed during the theme installation process. The vulnerability operates through unspecified vectors that typically involve the web server's handling of the uploaded files, potentially through decompression or extraction processes that execute embedded code. The flaw aligns with CWE-434, which specifically addresses unrestricted file uploads that can lead to arbitrary code execution.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise. Once exploited, attackers can gain control over the web server hosting the Dotclear installation, potentially leading to data breaches, service disruption, or use as a pivot point for attacking other systems within the network. The vulnerability affects organizations that rely on Dotclear for content management, particularly those with multiple administrators who may inadvertently grant elevated privileges to compromised accounts. The risk is amplified by the fact that the attack requires only authentication as a super administrator, which is often a privileged role that may have broader system access than typical user accounts.
Organizations should implement immediate mitigations including updating to patched versions of Dotclear, implementing strict file validation mechanisms, and restricting upload capabilities to only trusted administrators. The recommended approach involves deploying web application firewalls to monitor and filter file upload requests, enforcing strict content type validation, and implementing proper file access controls. Security teams should also conduct thorough audits of existing uploads and monitor for suspicious activity in the theme installation modules. This vulnerability demonstrates the critical importance of input validation and privilege separation in web applications, aligning with ATT&CK technique T1059 for command and script injection. Organizations should also consider implementing principle of least privilege controls to limit the scope of potential damage from compromised super administrator accounts, as well as regular security assessments to identify similar vulnerabilities in other web applications and CMS platforms.