This might not be too much of a WTF.
It very common, at least on UNIX to setup FTP accounts to be chroot-ed. This means that the default dir you drop them in now becomes / and they can't go any higher. It keeps people from getting into places they shouldn't be. The only problem is a lot of FTP servers on UNIX at least exec out to run the ls command.
But the ls command is in /bin and you can not longer get to the real /bin. So into order for it to work you have to make a copy in a bin directory under the chroot point. And on top of hat if ls requires any shared libs, you need them also.
I've seen plenty of places were ftp is used to pickup or push a file with a known name, ls would not be needed. If the sysadmins set the account up to be chroot-ed, and didn't follow up with making copies of ls into all the accounts, then you would get exactly what was seen, no WTF at all.