References https://www.cnblogs.com/pursue-security/p/18200086 https://www.javasec.org/java-vuls/FileUpload.html https://vulwiki.readthedocs.io/zh_CN/latest/web/fileupload/ https://blog.csdn.net/m0_65712362/article/details/132204031 https://jiwo.org/ken/detail.php?id=3272 https://portswigger.net/web-security/file-upload https://owasp.org/www-community/vulnerabilities/Unrestricted_File_Upload https://cloud.tencent.com/developer/article/2439519 https://www.cnblogs.com/backlion/p/13083120.html https://blog.hackall.cn/pentestvuln/692.html