Plain FTP protocol is unsecure. Makes no difference if it is Passive vs Active.
Now, there are other options, however, most for advance users though:
SSL options for FTP:
http://community.wdc.com/t5/My-Book-Live/How-to-setup-Secure-FTP-some-times-called-FTPS/td-p/534870
Other advance options as well: SCP/SFTP which work over SSH.
Do some searches on this forum, as others have mentioned it before.
