CVE-2016-7095 in Exponent
Summary
by MITRE
Exponent CMS before 2.3.9 is vulnerable to an attacker uploading a malicious script file using redirection to place the script in an unprotected folder, one allowing script execution.
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Analysis
by VulDB Data Team • 09/29/2022
The vulnerability identified as CVE-2016-7095 affects Exponent CMS versions prior to 2.3.9, representing a critical security flaw that enables unauthorized code execution through improper file upload validation mechanisms. This vulnerability resides within the content management system's file handling processes, specifically targeting the validation and sanitization of uploaded files. The flaw allows malicious actors to bypass security controls by exploiting a redirection mechanism that inadvertently places executable scripts in directories without proper access restrictions. The vulnerability demonstrates a clear failure in input validation and access control implementation, creating a path for remote code execution that could compromise the entire web application infrastructure.
The technical implementation of this vulnerability stems from insufficient validation of file upload operations within the CMS framework. Attackers can leverage a redirection technique to manipulate the file placement process, effectively circumventing the intended security boundaries that should prevent script execution in sensitive directories. This flaw operates at the intersection of improper input validation and inadequate access control measures, allowing malicious files to be placed in locations where they can be executed by the web server. The vulnerability's exploitation requires minimal privileges and can be executed through standard web browser interactions, making it particularly dangerous for widespread compromise. According to CWE classification, this represents a weakness in the validation of file uploads, specifically categorized under CWE-434 which addresses the improper handling of file uploads.
The operational impact of CVE-2016-7095 extends beyond simple unauthorized file placement, creating a comprehensive attack surface that enables full system compromise. Once an attacker successfully uploads a malicious script, they gain the ability to execute arbitrary code on the target server, potentially leading to complete system takeover, data exfiltration, and establishment of persistent backdoors. The vulnerability's exploitation can result in unauthorized access to sensitive data, modification of website content, and potential lateral movement within network environments where the compromised CMS resides. Organizations using affected versions face significant risk of data breaches and regulatory compliance violations, particularly in environments governed by standards such as iso 27001 and pci dss that mandate robust access control and input validation measures.
Mitigation strategies for this vulnerability require immediate implementation of security patches and comprehensive access control reviews. Organizations must upgrade to Exponent CMS version 2.3.9 or later, which includes fixed validation mechanisms for file uploads and improved redirection handling. Additional protective measures should include implementing strict file type validation, configuring web server directories to prevent script execution in upload folders, and establishing robust monitoring for suspicious file upload activities. The remediation process should align with industry best practices outlined in the mitre attack framework, particularly focusing on preventing initial compromise through proper input validation and access control measures. Network segmentation and web application firewalls can provide additional defense layers, while regular security assessments should verify that all upload mechanisms properly validate file content and enforce appropriate access controls to prevent similar vulnerabilities from emerging in other components of the application stack.