HP admits LaserJet flaw, refutes flaming printer hack

Columbia University researchers Salvatore Stolfo and Ang Cui claimed to have hijacked the software that controls LaserJet Printers' "Remote Firmware Update" process

HP has refuted claims by researchers at Columbia University that a security flaw in its HP's LaserJet printer could give a hacker remote access to the device and the power to set it on fire.

The reporting, first on MSNBC but also widely covered elsewhere on Tuesday, was "sensational and inaccurate", according to a statement by HP on Tuesday.

The firmware flaw the researchers discovered ran in the printer's "embedded systems", which are used to enrich services and functions available on printers.

The Columbia University researchers Salvatore Stolfo and Ang Cui claimed to have reverse engineered the software that controls LaserJet Printers' "Remote Firmware Update" process, allowing them to highjack a firmware upgrade.

They 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 brown and smoke, according to the report.

HP has said its printers contain a thermal breaker which would prevent the fuser from overheating or causing a fire.

"It cannot be overcome by a firmware change or this proposed vulnerability," it said.

Still, there was a key security omission in HP's software process. The printer's systems did not require a signature to verify the authenticity of the firmware update, which could allow an insider or a remote attacker to trick the printer to install malicious software.

Although labeling the reporting sensational, HP has conceded the vulnerability affects both internet facing and internally networked printers.

"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 said it was working on a firmware upgrade and would be alerting affected customers.

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Tags hackingHPColumbia Universitysecurity flawsSalvatore StolfHP LaserJet printerAng Cui

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