Synopsis
The remote FTP server is affected by a Denial of Service vulnerability.
Description
The remote host is using ProFTPD, a free FTP server for Unix and Linux.
According to its banner, the version of ProFTPD installed on the remote host is 1.3.2x prior to 1.3.2b or 1.3.3x prior to 1.3.3rc2 and is affected by a mitigation bypass vulnerability when the dNSNameRequired TLS option is enabled.
Solution
Upgrade to ProFTPD version 1.3.2b / 1.3.3rc2 or later.