The remote host is vulnerable to a globbing attack.
It is possible to make the remote FTP server crash by creating a large directory structure and then attempting to list it using wildcards. This is usually known as the 'ftp glob overflow' attack. An attacker can use this flaw to execute arbitrary code on the remote server, which may lead to remote shell access.
Upgrade your FTP server and/or libc. Consider removing directories writable by 'anonymous'.