CVE-2024-51499 in Markus
Summary
by MITRE • 11/18/2024
MarkUs is a web application for the submission and grading of student assignments. In versions prior to 2.4.8, an arbitrary file write vulnerability accessible via the update_files method of the SubmissionsController allows authenticated users (e.g. students) to write arbitrary files to any location on the web server MarkUs is running on (depending on the permissions of the underlying filesystem). e.g. This can lead to a delayed remote code execution in case an attacker is able to write a Ruby file into the config/initializers/ subfolder of the Ruby on Rails application. MarkUs v2.4.8 has addressed this issue. No known workarounds are available at the application level aside from upgrading.
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Analysis
by VulDB Data Team • 09/04/2025
The vulnerability identified as CVE-2024-51499 represents a critical arbitrary file write flaw within the MarkUs web application platform that serves as a submission and grading system for educational institutions. This vulnerability specifically affects versions prior to 2.4.8 and resides within the update_files method of the SubmissionsController component. The flaw enables authenticated users, including students who have legitimate access to the system, to exploit a path traversal or file manipulation vulnerability that allows them to write files to arbitrary locations on the underlying web server filesystem. This represents a significant security risk as it bypasses normal file system permissions and access controls that should normally restrict user activities to their designated areas within the application environment.
The technical nature of this vulnerability falls under CWE-22, which describes Path Traversal or Directory Traversal issues, where insufficient input validation allows attackers to manipulate file paths and gain unauthorized access to system resources. The exploitation occurs through the SubmissionsController's update_files method, which fails to properly validate or sanitize user-supplied file paths and content. When an authenticated user submits a file through this method, the application does not adequately verify that the target location falls within acceptable boundaries, enabling attackers to specify any file path on the server. This flaw is particularly dangerous because it operates within the context of an authenticated user session, meaning that attackers who gain access to student accounts can leverage this vulnerability without requiring additional privileged access.
The operational impact of this vulnerability extends beyond simple unauthorized file creation, as it can potentially enable delayed remote code execution attacks when combined with the ability to write files to specific directories within the Ruby on Rails application structure. The most concerning scenario occurs when an attacker can write a Ruby file into the config/initializers/ subfolder of the application, which is a critical location in Ruby on Rails applications where initialization files are executed during application startup. This allows attackers to execute arbitrary code within the context of the web application, potentially leading to complete system compromise, data exfiltration, or further lateral movement within the network infrastructure. The delayed nature of this execution means that the attack may not be immediately apparent, as the malicious code only executes when the application restarts or when the initializer files are processed.
Organizations utilizing MarkUs must prioritize immediate upgrade to version 2.4.8 or later to address this vulnerability, as no effective application-level workarounds exist to mitigate the risk. The vulnerability demonstrates the critical importance of proper input validation and access control mechanisms in web applications, particularly those handling user-generated content. Security practitioners should consider implementing additional monitoring and logging around file system operations, particularly in directories where application code is loaded or executed. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 for Command and Scripting Interpreter: Ruby, and T1078.004 for Valid Accounts: Cloud Accounts, as it leverages legitimate user credentials to execute malicious code. The vulnerability also aligns with T1566.002 for Phishing: Spearphishing Attachments, as attackers may need to gain initial access through social engineering to obtain student account credentials before exploiting this path traversal flaw. Given the nature of educational environments where multiple users have legitimate access to systems, this vulnerability highlights the importance of principle of least privilege enforcement and proper file system permission controls even within trusted user environments.