In this presentation at the 28c3 conference, Columbia University researchers Ang Cui and Jonathan Voris discuss firmware modification attacks against HP LaserJet printers.
The discussion centers on weaknesses within the firmware update process that allows an attacker to make arbitrary modifications to the NVRAM contents of the device.
"The attacks we present exploit a functional vulnerability common to all HP printers, and do not depend on any specific code vulnerability. These attacks cannot be prevented by any authentication mechanism on the printer, and can be delivered over the network, either directly or through a print server (active attack) and as hidden payloads within documents (reflexive attack)," the researchers explained.
Just last week, HP shipped patches for the vulnerabilities covered in this presentation.