The webmail service in 602 Lan Suite 2004.0.04.0909 and earlier allows remote attackers to cause a denial of service (CPU and memory consumption) by sending a POST request with a large Content-Length value, then disconnecting without sending that amount of data.
The Telnet proxy in 602 Lan Suite 2004.0.04.0909 and earlier allows remote attackers to cause a denial of service (socket exhaustion) via a Telnet request to an IP address of the proxy's network interface, which causes a loop.
The Telnet proxy of 602Pro LAN SUITE 2002 does not restrict the number of outstanding connections to the local host, which allows remote attackers to create a denial of service (memory consumption) via a large number of connections.