CVE-2023-38501 in copyparty
Summary
by MITRE • 07/26/2023
copyparty is file server software. Prior to version 1.8.7, the application contains a reflected cross-site scripting via URL-parameter `?k304=...` and `?setck=...`. The worst-case outcome of this is being able to move or delete existing files on the server, or upload new files, using the account of the person who clicks the malicious link. It is recommended to change the passwords of one's copyparty accounts, unless one have inspected one's logs and found no trace of attacks. Version 1.8.7 contains a patch for the issue.
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Analysis
by VulDB Data Team • 04/24/2025
The copyparty file server software presents a significant security vulnerability through reflected cross-site scripting flaws in versions prior to 1.8.7. This vulnerability manifests through specific URL parameters ?k304=... and ?setck=... which allow malicious actors to inject arbitrary script code into the application's response. The reflected nature of this XSS vulnerability means that the malicious payload is immediately reflected back to the user's browser without being stored on the server, making it particularly dangerous for targeted attacks. The vulnerability exists within the application's handling of user-supplied input in these specific parameter names, creating an attack surface that can be exploited through social engineering techniques where users are tricked into clicking malicious links.
The technical flaw stems from inadequate input validation and output encoding within the copyparty application's processing of these URL parameters. When the application receives these parameters and incorporates their values directly into the HTTP response without proper sanitization or encoding, it creates an environment where attacker-controlled data can be executed as client-side scripts. This vulnerability falls under CWE-79 which specifically addresses Cross-Site Scripting flaws, and represents a classic case of reflected XSS where the malicious input is immediately reflected back to the user. The vulnerability's exploitation potential is amplified by the fact that it can be leveraged to perform actions on behalf of authenticated users, as the malicious script would execute within the context of the victim's session.
The operational impact of this vulnerability extends beyond simple script execution to encompass serious data integrity and confidentiality risks. Attackers who successfully exploit this vulnerability can potentially manipulate file operations on the server including moving, deleting, or uploading files using the privileges of the victim user. This represents a significant escalation from typical XSS attacks, as it allows for persistent modification of server content rather than just session hijacking or data theft. The vulnerability creates a pathway for attackers to compromise the file server's content management capabilities, potentially leading to unauthorized data modification, content injection, or even complete server compromise depending on the user's privilege level. The attack vector is particularly concerning because it requires minimal technical expertise from the attacker and can be deployed through simple phishing campaigns or malicious links shared in communication channels.
Organizations using copyparty versions prior to 1.8.7 must implement immediate remediation measures to protect their file server infrastructure. The recommended approach involves upgrading to version 1.8.7 which contains the necessary patch to address the reflected XSS vulnerability. Additionally, system administrators should conduct thorough log analysis to identify any potential exploitation attempts, as the vulnerability may have been used to compromise accounts without detection. The patch implementation should include comprehensive input validation for all URL parameters, proper output encoding to prevent script execution, and enhanced session management controls. Security teams should also consider implementing web application firewalls to provide additional protection against similar vulnerabilities, and establish monitoring procedures to detect unusual file access patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and implementing proper input validation mechanisms to prevent common web application attacks that can lead to significant operational disruptions and data compromise.