Columbia University researchers Salvatore Stolfo and Ang Cui claimed to have hijacked the software that controls LaserJet Printers’ “Remote Firmware Update” process allowing them to highjack a firmware upgrade.
The two researchers demonstrated how they could instruct a highjacked printer’s fuser, designed to dry the ink, to abnormally heat up and cause a piece of paper to smoke. The researchers used HP’s laser printers to demonstrate their claim.
Professor Stolfo was quoted as saying “It’s like selling a car without selling the keys to lock it. It’s totally unsecure.”
HP issued the following statement:
Today there has been sensational and inaccurate reporting regarding a potential security vulnerability with some HP LaserJet printers. No customer has reported unauthorized access. Speculation regarding potential for devices to catch fire due to a firmware change is false.
HP LaserJet printers have a hardware element called a “thermal breaker” that is designed to prevent the fuser from overheating or causing a fire. It cannot be overcome by a firmware change or this proposed vulnerability.
While HP has identified a potential security vulnerability with some HP LaserJet printers, no customer has reported unauthorized access. The specific vulnerability exists for some HP LaserJet devices if placed on a public internet without a firewall. In a private network, some printers may be vulnerable if a malicious effort is made to modify the firmware of the device by a trusted party on the network. In some Linux or Mac environments, it may be possible for a specially formatted corrupt print job to trigger a firmware upgrade.
HP is building a firmware upgrade to mitigate this issue and will be communicating this proactively to customers and partners who may be impacted. In the meantime, HP reiterates its recommendation to follow best practices for securing devices by placing printers behind a firewall and, where possible, disabling remote firmware upload on exposed printers.
HP will continue to educate customers about security risks and the features available to address them, and take proactive steps to maintain the security of devices in the field. HP Imaging and Printing Security Solutions work directly at the device and on the network to protect information at rest and in motion, and to prevent unauthorized access.