Deep inside millions of computers is a special chip with the locks to highly guarded secrets...and now a former U.S. Army computer-security specialist has devised a way to break those locks.
The new attack discovered by Christopher Tarnovsky is difficult to pull off, partly because it requires physical access to a computer. Jeff Moss, founder of the Black Hat security conference and member of the U.S. Department of Homeland Security's advisory council, called Tarnovsky's finding "amazing."
Tarnovsky figured out a way to break chips that carry a "Trusted Platform Module," or TPM, designation by essentially spying on them like a phone conversation. Such chips are billed as the industry's most secure and are estimated to be in as many as 100 million personal computers and servers. When activated, the chips provide an additional layer of security by encrypting, or scrambling, data to prevent outsiders from viewing information on the machines. An extra password or identification such as a fingerprint is needed when the machine is turned on.
Many computers sold to businesses and consumers have such chips, though users might not turn them on. Users are typically given the choice to turn on a TPM chip when they first use a computer with it. If they ignore the offer, it's easy to forget the feature exists. However, computers needing the most security typically have TPM chips activated.
The chip Tarnovsky hacked is a flagship model from Infineon Technologies AG, the top maker of TPM chips. And Tarnovsky says the technique would work on the entire family of Infineon chips based on the same design. That includes non-TPM chips used in satellite TV equipment, Microsoft Corp.'s Xbox 360 game console and smart phones. That means his attack could be used to pirate satellite TV signals or make Xbox peripherals, such as handheld controllers, without paying Microsoft a licensing fee, Tarnovsky said. Microsoft confirmed its Xbox 360 uses Infineon chips, but would only say that "unauthorized accessories that circumvent security protocols are not certified to meet our safety and compliance standards."
The technique can also be used to tap text messages and e-mail belonging to the user of a lost or stolen phone. Tarnovsky said he can't be sure, however, whether his attack would work on TPM chips made by companies other than Infineon. Infineon said it knew this type of attack was possible when it was testing its chips. But the company said independent tests determined that the hack would require such a high skill level that there was a limited chance of it affecting many users.
Tarnovsky needed six months to figure out his attack, which requires skill in modifying the tiny parts of the chip without destroying it.
Using off-the-shelf chemicals, Tarnovsky soaked chips in acid to dissolve their hard outer shells. Then he applied rust remover to help take off layers of mesh wiring, to expose the chips' cores. From there, he had to find the right communication channels to tap into using a very small needle. The needle allowed him to set up a wiretap and eavesdrop on all the programming instructions as they are sent back and forth between the chip and the computer's memory. Those instructions hold the secrets to the computer's encryption, and he didn't find them encrypted because he was physically inside the chip. Even once he had done all that, he said he still had to crack the "huge problem" of figuring out how to avoid traps programmed into the chip's software as an extra layer of defense.
Is it a hack if somebody else has physical use of your computer? I don't think so. But remember, if you have a seasoned computer hacker with access to chemicals and unlimited time to mess with your system, things don't look so good for you.
The new attack discovered by Christopher Tarnovsky is difficult to pull off, partly because it requires physical access to a computer. Jeff Moss, founder of the Black Hat security conference and member of the U.S. Department of Homeland Security's advisory council, called Tarnovsky's finding "amazing."Tarnovsky figured out a way to break chips that carry a "Trusted Platform Module," or TPM, designation by essentially spying on them like a phone conversation. Such chips are billed as the industry's most secure and are estimated to be in as many as 100 million personal computers and servers. When activated, the chips provide an additional layer of security by encrypting, or scrambling, data to prevent outsiders from viewing information on the machines. An extra password or identification such as a fingerprint is needed when the machine is turned on.
Many computers sold to businesses and consumers have such chips, though users might not turn them on. Users are typically given the choice to turn on a TPM chip when they first use a computer with it. If they ignore the offer, it's easy to forget the feature exists. However, computers needing the most security typically have TPM chips activated.
The chip Tarnovsky hacked is a flagship model from Infineon Technologies AG, the top maker of TPM chips. And Tarnovsky says the technique would work on the entire family of Infineon chips based on the same design. That includes non-TPM chips used in satellite TV equipment, Microsoft Corp.'s Xbox 360 game console and smart phones. That means his attack could be used to pirate satellite TV signals or make Xbox peripherals, such as handheld controllers, without paying Microsoft a licensing fee, Tarnovsky said. Microsoft confirmed its Xbox 360 uses Infineon chips, but would only say that "unauthorized accessories that circumvent security protocols are not certified to meet our safety and compliance standards."
The technique can also be used to tap text messages and e-mail belonging to the user of a lost or stolen phone. Tarnovsky said he can't be sure, however, whether his attack would work on TPM chips made by companies other than Infineon. Infineon said it knew this type of attack was possible when it was testing its chips. But the company said independent tests determined that the hack would require such a high skill level that there was a limited chance of it affecting many users.
Tarnovsky needed six months to figure out his attack, which requires skill in modifying the tiny parts of the chip without destroying it.
Using off-the-shelf chemicals, Tarnovsky soaked chips in acid to dissolve their hard outer shells. Then he applied rust remover to help take off layers of mesh wiring, to expose the chips' cores. From there, he had to find the right communication channels to tap into using a very small needle. The needle allowed him to set up a wiretap and eavesdrop on all the programming instructions as they are sent back and forth between the chip and the computer's memory. Those instructions hold the secrets to the computer's encryption, and he didn't find them encrypted because he was physically inside the chip. Even once he had done all that, he said he still had to crack the "huge problem" of figuring out how to avoid traps programmed into the chip's software as an extra layer of defense.
Is it a hack if somebody else has physical use of your computer? I don't think so. But remember, if you have a seasoned computer hacker with access to chemicals and unlimited time to mess with your system, things don't look so good for you.
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