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Using Substitute User or "su" Commands to Change SFTP Login Credentials

Some security policies do not allow for remote logon using privileged accounts such as Administrator or root. In these situations, you can logon and then change user privileges from within the session using the "Substitute User" and "su" commands that are available starting with SecureFX® 6.1, SecureCRT® 6.1, and VanDyke ClientPack 6.1. The "Substitute User" and "su" commands are unique to VanDyke Software applications, and require VShell® 3.5 or later for Windows.

In SecureFX, the Tools menu has a "Subsitute User" command that opens a logon dialog. In the SecureCRT SFTP Tab window, the command is invoked with "su <username>". The vsftp utility delivered in the VanDyke ClientPack 6.1 and the VShell 3.5 server for Windows also support "su". It is enabled by default in the VShell 3.5 server for Windows.

Running "Substitute User" from SecureFX

  1. Open a remote session.
  2. Select the "Substitute User" command from the Tools menu.
  3. Enter the new username and password in the su dialog.
  4. When finished, select "Exit Substitute User" from the Tools menu.

Running "su" from SecureCRT's SFTP Tab

  1. Open the SFTP tab.
  2. At the "sftp>" prompt, enter "su <username>".
  3. Enter your password when prompted.
  4. Perform file transfer commands as needed.
  5. Use the "exit" command to return to your previous logon privileges.

Note: To run "su" with the "vsftp" ClientPack command-line utility, follow steps 2 through 5 as outlined above in the instructions for running the "su" command from a SecureCRT SFTP tab.

"su" is most useful for remote logins where privileged accounts are not allowed on entry. Note that SFTP root directory settings do not change after a "su" command.

You can try the "Substitute User" and "su" commands by downloading SecureFX, SecureCRT, or the VanDyke ClientPack today (note that VShell 3.5 for Windows server or later is required).

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