CVE-2020-13240 in Dolibarr
Summary
by MITRE
The DMS/ECM module in Dolibarr 11.0.4 allows users with the 'Setup documents directories' permission to rename uploaded files to have insecure file extensions. This bypasses the .noexe protection mechanism against XSS.
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Analysis
by VulDB Data Team • 05/21/2020
The vulnerability identified as CVE-2020-13240 resides within the Document Management System/Enterprise Content Management module of Dolibarr version 11.0.4, representing a critical security flaw that undermines the platform's file handling mechanisms. This issue specifically targets users who possess the 'Setup documents directories' permission level, granting them elevated privileges that can be exploited to manipulate file extensions in ways that compromise system security. The vulnerability manifests through a direct bypass of the system's inherent .noexe protection mechanism, which is specifically designed to prevent cross-site scripting attacks by restricting executable file uploads.
The technical flaw operates through a path traversal and file extension manipulation attack vector where authenticated users can rename uploaded files to include potentially dangerous extensions such as .php, .asp, or .jsp despite the system's protective measures. This occurs because the application fails to properly validate or sanitize file extensions during the renaming process, allowing malicious actors to circumvent the intended security controls. The .noexe protection mechanism, which typically prevents files with executable extensions from being stored in document directories, becomes ineffective when users can rename existing files to include these dangerous extensions. This flaw directly relates to CWE-73, which addresses "External Control of File Name or Path" and represents a classic case of insufficient input validation combined with improper access controls.
The operational impact of this vulnerability extends beyond simple file manipulation, as it creates a pathway for potential code execution and remote code injection attacks. Attackers who can exploit this vulnerability may upload malicious files with innocuous extensions such as .jpg or .pdf, then rename them to .php or similar executable formats, effectively bypassing the security layer designed to prevent such attacks. This creates a persistent threat vector that could allow unauthorized users to execute arbitrary code on the server, potentially leading to full system compromise. The vulnerability is particularly concerning in enterprise environments where Dolibarr is used for document management and collaboration, as it could enable attackers to gain unauthorized access to sensitive business data and systems.
Mitigation strategies for CVE-2020-13240 should focus on implementing comprehensive input validation and access control measures. Organizations should immediately restrict the 'Setup documents directories' permission to only trusted administrators, implement strict file extension validation that prevents renaming operations from introducing executable extensions, and deploy additional security controls such as mandatory file type detection and content validation. The solution should include proper sanitization of all file operations, ensuring that file extensions cannot be modified to include dangerous patterns, and implementing a robust file type verification mechanism that operates independently of user permissions. This vulnerability aligns with ATT&CK technique T1059, which covers "Command and Scripting Interpreter," as it enables the execution of malicious code through manipulated file extensions, and T1078, which addresses "Valid Accounts," since the attack requires legitimate user privileges to be effective.
The broader implications of this vulnerability highlight the importance of defense-in-depth strategies in enterprise security architectures. Organizations using Dolibarr or similar document management systems should conduct comprehensive security assessments to identify similar path traversal and file manipulation vulnerabilities across their software ecosystem. Regular security updates and patch management processes become critical, as this vulnerability demonstrates how seemingly minor permission flaws can create significant security risks. The incident underscores the necessity of implementing automated security controls that can detect and prevent unauthorized file extension modifications, particularly in systems where file upload and management capabilities are exposed to authenticated users. Additionally, organizations should consider implementing network-level protections such as web application firewalls and intrusion detection systems to monitor for suspicious file manipulation activities that could indicate exploitation attempts.