An issue was discovered on MOXA Mgate MB3180 Version 2.1 Build 18113012. Attackers can use slowhttptest tool to send incomplete HTTP request, which could make server keep waiting for the packet to finish the connection, until its resource exhausted. Then the web server is denial-of-service.
https://github.com/shekyan/slowhttptest
https://github.com/Jian-Xian/CVE-POC/blob/master/CVE-2021-33824.md