CVE-2020-13239 in Dolibarr
Summary
by MITRE
The DMS/ECM module in Dolibarr 11.0.4 renders user-uploaded .html files in the browser when the attachment parameter is removed from the direct download link. This causes XSS.
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Analysis
by VulDB Data Team • 05/21/2020
The vulnerability CVE-2020-13239 resides within the DMS/ECM module of Dolibarr version 11.0.4, a widely used open-source ERP and CRM system. This security flaw represents a critical cross-site scripting vulnerability that emerges when users upload html files to the system and subsequently access them through direct download links. The issue stems from the application's improper handling of user-generated content, specifically when the attachment parameter is stripped from download URLs, allowing browsers to render the html content directly rather than forcing a download. This behavior creates an exploitable condition where malicious actors can craft html files containing malicious javascript payloads that execute in the context of authenticated users' browsers. The vulnerability directly maps to CWE-79, which identifies cross-site scripting flaws as weaknesses in web applications that allow attackers to inject client-side scripts into web pages viewed by other users. From an operational perspective, this vulnerability poses significant risks to organizations using Dolibarr for document management and collaboration, as it enables attackers to execute arbitrary code in the browsers of legitimate users who view compromised files.
The technical exploitation of this vulnerability requires an attacker to upload a specially crafted html file containing malicious javascript code to the Dolibarr system. When users navigate to the file through a direct download link without the attachment parameter, the browser renders the html content directly, executing any embedded scripts. This creates a persistent threat vector where attackers can steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users. The vulnerability is particularly concerning because it leverages the trust relationship between the application and its users, allowing attackers to exploit legitimate access patterns to deliver malicious payloads. The attack surface expands when considering that Dolibarr is commonly used in business environments where users frequently share documents and collaborate on projects, making the potential for exploitation more likely. This flaw aligns with ATT&CK technique T1566.001, which describes social engineering attacks through spearphishing with malicious attachments, where the malicious html files serve as the payload delivery mechanism.
Organizations utilizing Dolibarr should immediately implement multiple layers of mitigation to address this vulnerability. The primary remediation involves upgrading to a patched version of Dolibarr where the DMS/ECM module properly handles html file rendering or enforces download behavior regardless of URL parameters. System administrators should also implement content validation mechanisms that sanitize or reject html files from user uploads, particularly when these files may be accessed through direct links. Network-level protections such as web application firewalls can help detect and block malicious payloads, while user education programs should emphasize the risks of accessing untrusted files from collaboration platforms. Additionally, organizations should consider implementing strict access controls and monitoring for unusual file upload patterns that might indicate attempted exploitation. The vulnerability demonstrates the importance of proper input validation and output encoding in web applications, particularly when dealing with user-generated content that may be rendered directly in browser contexts. Security teams should also review their incident response procedures to ensure rapid detection and remediation of similar vulnerabilities in other enterprise applications that handle user uploads and document sharing.