Boffins deduce chip's crypto just by looking at it
Smartcard hacking enters script-kiddie phase
Black Hat Hackers have released tools that unlock the software stored on heavily fortified chips so researchers can independently assess their security and spot weaknesses.
At the heart of the the release, which was announced Wednesday at the Black Hat Security conference in Las Vegas, is Degate, software developed by Martin Schobert for hardware experts to analyze small silicon structures. It has recently been refined so it can be used by amateurs to analyze chips the size of smartcards.
The tools are the work of cryptographer Karsten Nohl and hardware hacker Christopher Tarnovsky, who are both veteran reverse engineers of extremely sophisticated smart chips.
In 2008, Nohl and a team of colleagues cracked the encryption of the widely used Mifare Classic smartcard after physically dissecting its circuitry and analyzing it with a microscope and optical recognition software. The 18-month task uncovered a proprietary algorithm on one of the chips generated cryptographically weak outputs that allowed attackers to break or clone an individual card in just minutes.
And last year, Tarnovsky cracked the Infineon SLE 66PE one of the most locked-down chips ever put into a consumer device, through a grueling six-month process that involved an electron microscope, microscopic needles, and a steady supply of microcontrollers bought on the surplus market in Hong Kong.
“We found a way now to give everybody the ability to extract software out of smartcards,” Nohl, who is chief scientist at Berlin-based Security Research Labs, told The Register. Degate “can be used by less skilled people, but the results are even more expressive than they were before.”
He estimated that had Degate existed in its current form then, it would have taken a few weeks to reverse engineer the Mifare card.
He compared Degate to disassembler software used by researchers to analyze hundreds of thousands of lines of binary code to figure out how it works.
“Degate is essentially a disassembler in the hardware world,” Nohl said.
The software recognizes structures on chips, traces the connections between them, and pieces together the algorithms implemented by the circuits.
Nohl said the tools are intended to make it easier for software experts to assess the security of chips stored on credit cards and other types of smartcards.
“These smartcards are being abused today for storing proprietary protocols and keeping them away from independent analysis,” he said. “We want to help the software hackers to find more interesting software for analysis.” ®