no, you can only su with a server user account.... You trying to hack a system?

nope just finding out the harm a ftp user can do,or the things he/she can find out about my server with a simple ftp account thank you men

su is used to connect with server user from root or to root

Normally you have to be logged in to a shell to do su or sudo. I would highly doubt any FTP servers would accept su or sudo commands. One exception might be if you are using something such as WinSCP in SCP mode which actually is connecting using a shell, but allows uploading and downloading files - then it will typically also allow shell commands.

I use winscp and have thrown shell commands too so if I do it so will other guy that I give a ftp user for my server.is true thank you then how I do if I require an install on my server performed by a company ?,it aint that safe to trust them in order to grant them ftp access or is it?

Most FTP servers you declare the home directory and permissions for a user. Then they cannot get to a directory higher than their root directory.

If you are using SCP protocol when using WinSCP it can do shell commands. If you are using FTP protocol I don't think most FTP servers allow executing files, etc.

I dont think is good to underestimate the damage anybody can do to ur server with a ftp account,I just entered some shell command on winscp and got all this code just like if I was on putty:
PHP 5.2.17 (cli) (built: Feb 16 2012 23:29:39)
Copyright (c) 1997-2010 The PHP Group
Zend Engine v2.2.0, Copyright (c) 1998-2010 Zend Technologies
with the ionCube PHP Loader v4.0.14, Copyright (c) 2002-2011, by ionCube Ltd., and
with Zend Extension Manager v1.2.0, Copyright (c) 2003-2007, by Zend Technologies
with Zend Optimizer v3.3.9, Copyright (c) 1998-2009, by Zend Technologies

imagine hon what they could fetch with the right command

What protocol are you using in WinSCP for it to connect? If it is using SCP then yes you can execute shell commands, because that is how it is actually connecting, using the shell. See if you can do anything with the protocol set to FTP.

I usually login with winscp using my root,trying to access to it with my root with ftp 'protocol' is impossible,something that might lead me to think that a ftp created user the same way wont be able to connect via sftp or other protocol thereforely he/she wont be able to perform any shell commands,do you agree porcupine73?
thanks

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