CVE-2020-13145 in Open edX Ironwood
Summary
by MITRE
Studio in Open edX Ironwood 2.5 allows users to upload SVG files via the "Content>File Uploads" screen. These files can contain JavaScript code and thus lead to Stored XSS.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 05/19/2020
The vulnerability CVE-2020-13145 resides within the Open edX Ironwood 2.5 learning management system, specifically within the Studio component that governs content management and user interactions. This issue manifests through the file upload functionality that permits users to submit SVG (Scalable Vector Graphics) files through the Content>File Uploads interface. The vulnerability stems from insufficient input validation and sanitization mechanisms that fail to properly filter malicious content embedded within SVG files. When users upload SVG files containing embedded JavaScript code, the system does not adequately strip or neutralize the potentially harmful script elements, creating a persistent security risk.
The technical flaw represents a classic stored cross-site scripting vulnerability classified under CWE-116 as improper neutralization of special elements used in stored data. Attackers can craft malicious SVG files containing JavaScript payload that executes when other users view the uploaded content within the Studio interface. This stored XSS vulnerability operates through the SVG file upload mechanism because SVG format supports embedded scripts and external references that can be interpreted by web browsers. The vulnerability is particularly concerning as it leverages the legitimate file upload functionality that users expect to work normally, making it difficult to detect and prevent through standard security monitoring.
The operational impact of this vulnerability extends beyond simple script execution as it provides attackers with persistent access to user sessions and potentially sensitive course content. When authenticated users browse to pages containing the malicious SVG files, their browsers execute the embedded JavaScript code, which can steal session cookies, redirect users to malicious sites, or manipulate course content. The stored nature of the vulnerability means that the malicious code remains active until manually removed by administrators, creating a long-term threat vector that can be exploited repeatedly. This vulnerability affects not only individual user sessions but also compromises the integrity of the entire course management system.
Organizations should implement immediate mitigations including comprehensive SVG file validation that strips all script elements, implements Content Security Policy headers to prevent script execution, and restricts file upload permissions to trusted administrators only. The solution should incorporate proper input sanitization using libraries designed to handle SVG content safely, such as DOMPurify or similar security-focused libraries. Additionally, implementing file type restrictions that limit uploads to specific safe formats and conducting regular security audits of uploaded content can significantly reduce the risk. According to ATT&CK framework, this vulnerability maps to T1059.007 for scripting and T1566.001 for malicious file execution, emphasizing the need for layered defensive measures including user education and network monitoring to detect potential exploitation attempts.