This role of combined GIS user and UNIX system administrator is common within the GIS community. However, if you are using these services, you should be concerned. If you only use UNIX servers in anonymous ftp or web sessions to get or put data, you are not actually logging in as a user with a password. Note that the user-id and password are sent across in clear text. Proof of this, for the doubtful, is below.
Packet sniffers can easily steal user-ids and passwords.
Use of snoop, sniffit, snort, or other packet sniffers by malicious users compromises the security of the network. In a typical networked configuration, a malicious user can plug into the network with a Linux machine, and snoop network traffic for user-ids and passwords. Any UNIX machine on the subnet can log user-ids and passwords from ftp or telnet sessions. This example uses snoop running on a Solaris 7 machine. A user logged in as root runs snoop , and logs the output to a file called snoop.out .