Easiest way is to allow direct login with the user account you need, if it is not allowed already. For accounts such as
root, the direct login is typically disabled by default for security reasons. So when enabling it, have security in mind.
Particularly with SSH, you may want to keep password authentication (the most vulnerable one) disabled and use e.g. public key authentication instead. With OpenSSH server, you can do that by setting
In some cases (with Unix/Linux server) you may be able to use
sudo command straight after login to change a user, before file transfer session starts.
FTP protocol does not allow this.
With SFTP protocol, you can use SFTP server option on SFTP page of Advanced Site Settings dialog to execute SFTP binary under a different user. With OpenSSH server, you can specify:
Note that SFTP server binary may be located elsewhere2 (e.g. in
With SCP protocol, you can specify following command as custom shell on the SCP/Shell page of Advanced Site Settings dialog:
However you will not be able to provide a password for
su (see remote command execution limitations). So you may be able to do the above only if you are allowed to do
sudo su without being prompted with password. See
sudo documentation to learn how to do that. For example you can add following line to
sudoers file (
yourusername ALL=NOPASSWD: ALL
The above line is very permissive, it allows user
yourusername connected from anywhere (the first
ALL) to run any command (the second
ALL) as a
root without being asked for password. So you should restrict it as much as possible.
For example with OpenSSH you may restrict it only to SFTP session by:
yourusername ALL=NOPASSWD: /bin/sftp-server
Note that as WinSCP cannot implement terminal emulation, you need to have
requiretty turned off (which is default).