ISPConfig3 pure-ftpd giving access to sda /

[Croydon]

I don't know if it helps in your case but I had this on a debian server, too.
I do not remember 100%, but I had to change one of

/etc/pure-ftpd/conf/ChrootEveryone
or the setting in
/etc/default/pure-ftpd-common (VIRTUALCHROOT)

Although it did not really make sense I had to change one of them to false / no and it worked. Trying doesn't hurt, does it?