CVE-2010-5091 in SilverStripe
Summary
by MITRE
The setName function in filesystem/File.php in SilverStripe 2.3.x before 2.3.8 and 2.4.x before 2.4.1 allows remote authenticated users with CMS author privileges to execute arbitrary PHP code by changing the extension of an uploaded file.
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Analysis
by VulDB Data Team • 12/12/2021
The vulnerability identified as CVE-2010-5091 represents a critical security flaw in the SilverStripe content management system that affects versions prior to 2.3.8 and 2.4.1. This issue resides within the filesystem/File.php component and specifically targets the setName function which handles file naming operations. The vulnerability exploits a weakness in the file extension validation mechanism that allows authenticated users with CMS author privileges to bypass security controls and execute arbitrary PHP code on the affected server.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the setName function. When users upload files through the CMS interface, the system should properly validate file extensions to prevent malicious code execution. However, the flawed implementation allows attackers to manipulate file extensions by simply changing the file name during the upload process. This weakness enables an attacker to upload a file with a PHP extension, effectively creating a backdoor or web shell that can be executed by the web server, thereby granting the attacker persistent access to the server.
The operational impact of this vulnerability is severe and multifaceted. An authenticated attacker with CMS author privileges can leverage this flaw to gain full control over the web server hosting the SilverStripe application. The remote execution capability means that attackers do not require physical access to the server and can operate entirely through the web interface. This vulnerability directly violates the principle of least privilege and can lead to complete system compromise, data exfiltration, and potential lateral movement within network environments. The attack vector is particularly dangerous because it requires minimal privileges to exploit, making it accessible to users who should only have limited content management capabilities.
This vulnerability aligns with CWE-434, which describes "Unrestricted Upload of File with Dangerous Type" and corresponds to ATT&CK technique T1190, "Exploit Public-Facing Application." The flaw demonstrates poor input validation practices and inadequate file handling security measures that are common in web applications. Organizations running affected SilverStripe versions face significant risk of unauthorized access, data breaches, and potential system takeover. The vulnerability also highlights the importance of proper file extension validation and the necessity of implementing robust security controls around file upload functionalities. Organizations should immediately implement patches to address this vulnerability, as the timeframe between the vulnerability disclosure and potential exploitation by threat actors can be extremely short. The remediation process requires updating to the patched versions of SilverStripe 2.3.8 and 2.4.1, which contain proper validation mechanisms to prevent malicious file extension manipulation. Additionally, security monitoring should be enhanced to detect suspicious file upload activities and to verify that proper file type restrictions are enforced across all CMS interfaces.