Braving the Cold (Boot) – A Sneak Peek of My Presentation at Black Hat

by Patrick McGregor

Cold boot attacks aren’t theoretical academic exercises. Cold boot attacks are real. And they’re serious.

In the past few years, companies have poured hundreds of millions of dollars into full disk encryption technologies. Companies expect full disk encryption to reduce the risk of exposure of sensitive information such as intellectual property or customer data. Reality often deviates from what is expected, however. Researchers from Princeton shocked the industry earlier in 2008 when they released a research paper that showed that low-cost “Cold Boot” attacks could be used to defeat the security of most full disk encryption systems. They recently even published all the tools needed to do this at home!

Some have argued that Cold Boot attacks are not serious security threats. I disagree! First, an unskilled person can capitalize on the exploit using simple, automated steps and publicly available tools. In fact, Cold Boot attacks require nothing more than plugging a USB drive into a laptop. Second, the physical target of a Cold Boot attack, such as a laptop, is very easily obtainable (see the recent Ponemon report on laptops lost/stolen in airports – scary!). Third, although many laptops and desktops are stolen via random acts of theft, it is well known that some criminals profit from organized, calculated data theft. It is only a matter of time before we hear of a high-profile data breach that results from a simple Cold Boot attack.

I am excited to present at Black Hat several innovations for preventing Cold Boot attacks. In addition to summarizing how a Cold Boot attack works, I’ll describe four new software techniques for hardening full disk encryption against the attacks. The software technology was developed by myself, Tim Hollebeek, Alexander Volynkin, and Matt White. All of us work for BitArmor, an exciting security startup based in Pittsburgh. Here’s a sneak peek:

· Wash up: Wipe keys immediately before certain OS state transitions, such as before the computer shuts down or goes into hibernation mode – accessing the memory will yield nothing.

· Take advantage of BIOS memory smashing: By strategically placing keys in certain regions of memory, we can rely on the BIOS boot process to overwrite keys before any operating system can dump the contents of memory.

· Is it chilly in here?: Using built-in temperature sensors, we can lock down the system in reaction to temperature drops that may indicate a Cold Boot attack is in progress.

· Create a virtual enclave for keys: We can implement special cryptographic, OS and processor architecture techniques to provide robust protection for keys against the most aggressive cold boot attacks. By creating a “virtual secure enclave” for encryption keys in software, an attacker cannot extract critical keys from memory – even if the RAM is super-cooled.

Hope you can join us at Black Hat as we take an in-depth look at the future of full disk encryption technology.