CVE-2005-3767 in Exponent
Summary
by MITRE
Exponent CMS 0.96.3 and later versions does not properly restrict the types of uploaded files, which allows remote attackers to upload and execute PHP files.
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Analysis
by VulDB Data Team • 06/11/2019
The vulnerability identified as CVE-2005-3767 affects Exponent CMS versions 0.96.3 and later, presenting a critical security flaw in file upload validation mechanisms. This weakness stems from insufficient input sanitization and access control measures within the content management system's file handling functionality. The vulnerability allows malicious actors to bypass intended restrictions and upload arbitrary PHP files to the target server, creating a severe attack surface that can be exploited for remote code execution.
The technical implementation of this vulnerability resides in the CMS's file upload component where proper MIME type checking and file extension validation are either absent or inadequately implemented. Attackers can exploit this flaw by crafting malicious PHP files with seemingly benign extensions or by manipulating the upload process to circumvent built-in security checks. The vulnerability directly maps to CWE-434, which describes insecure file upload vulnerabilities where applications accept files without proper validation of their content or type. This weakness enables attackers to upload web shells or other malicious code that can be executed within the web server context, potentially leading to full system compromise.
The operational impact of this vulnerability extends beyond simple unauthorized file uploads, as it provides attackers with persistent access to the target system. Once a malicious PHP file is successfully uploaded and executed, attackers can establish backdoors, escalate privileges, and perform further reconnaissance within the network. The vulnerability aligns with ATT&CK technique T1505.003, which covers the use of web shells for maintaining access and executing commands on compromised systems. This type of vulnerability is particularly dangerous in web application environments where CMS platforms are frequently targeted due to their widespread use and the potential for privilege escalation through file execution.
Mitigation strategies for CVE-2005-3767 should focus on implementing robust file validation mechanisms including strict MIME type checking, whitelisting of allowed file extensions, and proper file content verification. Organizations should ensure that all file uploads are processed through secure channels with proper authentication and authorization controls. The recommended approach includes configuring the web server to prevent execution of uploaded files in web-accessible directories, implementing proper file permission controls, and regularly updating the CMS to versions that address this specific vulnerability. Security professionals should also consider implementing network-based intrusion detection systems to monitor for suspicious upload activities and maintain comprehensive logging of all file operations for forensic analysis purposes.