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You may have already read about cold attacks. In 2013, researchers threw the Samsung Galaxy Nexus in the freezer to prepare it for an attack. This week, the F-Secure duo from Helsinki showed a similar hack on Lenovo's laptop. Researchers Olle Segerdahl and Pasi Saarinen used a cold attack to steal system encryption keys.
Do not weaken your protection just because Segerdal and Saarinen decide to attack the Lenovo laptop, and you accidentally have a different brand of computer. The technique they used could theoretically be used against any laptop on the market, including Apple.
While your laptop is in sleep mode, when you close the lid or after a certain period of inactivity, it is probably vulnerable. This is how their attack works.
Instead of putting the entire laptop in the refrigerator, F-Secure used a more selective cooling process. The bottom cover of the laptop was removed, and the system’s RAM was quickly cooled using a can of compressed air. Notice, not just dropping it with air, turn it over and direct liquid fluorocarbons into the chip.
Once the chip has cooled sufficiently, a second phase of attack may begin. A specialized (but fairly common) device allows them to manipulate non-volatile system memory. As soon as the tool does its job, the attacker instructs the computer to boot from the USB drive. Any data that was saved in memory when the computer went into sleep mode is now available. In this case, the hacker can reset the "secret password".
How to protect yourself from cold attacks
No matter how dangerous they may be, cold start attacks are not so difficult to defend. One of the simplest protections is to transfer the PC not to sleep mode, but to hibernation. Hibernation does not leave the same digital traces in memory as a dream, which neutralizes the attack. Setting a pre-boot password on your computer adds another layer of protection.
It is important to be prepared, no matter how you think, the likelihood that you will be subjected to a cold boot attack. “Planning these events is better than assuming that hackers cannot physically compromise the devices, because this is clearly not the case,” Segerdal notes.
