SimianOpinion

We first present several generic firmware modification attacks against HP printers. Weaknesses within the firmware update process allows the 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).