Race Condition in Sparx Pro Cloud Server

Summary

Sparx Pro Cloud Server is vulnerable to a Race Condition in the /data_api/dl_internal_artifact.php endpoint. The application downloads the properties of the object pointed by guid parameter and saves loaded content in current location (__DIR__) under the specified name. An attacker with repository access can control both the filename and file contents, allowing the creation of a malicious PHP file in a current directory. Although the file is deleted after processing, a race condition exists: if the response transmission is delayed (e.g., via a large file or slow client connection), the file remains accessible. During this window, the attacker can issue a second request to execute the malicious PHP file, resulting in remote code execution. The vendor was notified early about this vulnerability, but didn't respond with the details of vulnerability or vulnerable version range. Only version 6.1 (build 167) and below were tested and confirmed as vulnerable, other versions were not tested and might also be vulnerable.