source: http://www.securityfocus.com/bid/2659/info

A remote vulnerability exists in Tektronix Phaser network printers in the 7xx, 8xx, and 9xx series.

An attacker with access to the printer's local network (or, if no firewall is in place, any attacker) can reach the printer's admin interface, supported by the inbuilt Tektronix PhaserLink webserver.

No authentication is applied to this connection. Arbitrary pages inside the printer's administration interface may be accessed by specifying the desired page in a querystring submitted to the PhaserLink webserver.

No password or other authentication method prevent arbitrary users from making use of this interface.

Using this method, an attacker can activate the printer's 'Emergency Power Off' feature.

This can lead to improper cooling of the ink/crayon reservoir, physically damaging the device.

* The vendor has reported that the printer properly handles 'Emergency Power Off' situations, and that physical damage is unachievable.

Submit http://printername/_ncl_items.shtml&SUBJECT=1

Select "Shutdown" option = "Emergency Power Off".