CVE-2020-15907 in Mahara
Summary
by MITRE
In Mahara 19.04 before 19.04.6, 19.10 before 19.10.4, and 20.04 before 20.04.1, certain places could execute file or folder names containing JavaScript.
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Analysis
by VulDB Data Team • 08/08/2020
CVE-2020-15907 represents a cross-site scripting vulnerability in the Mahara learning management system that allows attackers to inject malicious JavaScript code through file or folder names. This vulnerability affects multiple versions of Mahara including 19.04 before 19.04.6, 19.10 before 19.10.4, and 20.04 before 20.04.1, indicating a widespread issue that persisted across several release branches. The flaw occurs in the way the system handles user-provided filenames, specifically when these names contain JavaScript code that gets executed in the browser context. This represents a classic XSS vulnerability where untrusted input is not properly sanitized or encoded before being rendered in the user interface. The vulnerability is categorized under CWE-79 as Cross-site Scripting, which is a well-documented weakness in web applications where malicious scripts are injected into trusted websites. The attack vector typically involves an attacker creating or uploading files with JavaScript payloads in their names, which are then displayed to other users within the Mahara interface, potentially leading to session hijacking, data theft, or redirection to malicious sites. The operational impact is significant as it can affect any user who views the maliciously named files or folders, particularly in collaborative environments where users frequently upload and share content. The vulnerability can be exploited through various means including direct file uploads, shared folder creation, or even through the file management interface where users can rename existing files. This issue directly aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, as it enables the execution of malicious JavaScript code within the browser context. The vulnerability demonstrates poor input validation and output encoding practices, where the system fails to properly escape special characters in filenames before rendering them in HTML contexts. Organizations using affected Mahara versions face potential security risks including unauthorized access to user sessions, data exfiltration, and the ability for attackers to perform actions on behalf of legitimate users. The remediation involves updating to the patched versions of Mahara, specifically 19.04.6, 19.10.4, and 20.04.1, which implement proper sanitization of filenames and ensure that JavaScript code cannot be executed through file or folder names. Additionally, administrators should consider implementing content security policies and regular security audits to detect and prevent similar vulnerabilities in other components of the system.
The vulnerability exposes a fundamental security flaw in how web applications handle user-generated content, particularly in file management systems where filenames are displayed directly in the user interface. When user-supplied data is not properly escaped or validated before being rendered, it creates opportunities for attackers to inject malicious code that executes in the context of other users' browsers. This type of vulnerability is particularly dangerous in educational platforms like Mahara, where users frequently share files and collaborate on projects, making it easier for attackers to find valid targets. The issue highlights the importance of implementing defense-in-depth strategies, including input validation, output encoding, and secure coding practices. Organizations should also consider implementing web application firewalls and monitoring for suspicious file naming patterns that could indicate attempted exploitation. The vulnerability serves as a reminder of the critical need for regular security updates and the importance of maintaining current versions of all software components, as outdated systems often contain known vulnerabilities that can be easily exploited by threat actors. This particular flaw demonstrates how seemingly innocuous features like file naming can become security risks when proper input sanitization is not implemented throughout the application's codebase.