Feeds

Bitlocker hack is easily prevented, Microsoft says

Restoring Vista disk crypto's good name

The Power of One eBook: Top reasons to choose HP BladeSystem

A disk encryption system built into Windows Vista remains a viable way to protect sensitive files, according to Microsoft. In a blog posting, Russ Humphries, senior product manager for Windows Vista Security, outlined simple steps that users can take to prevent an attack laid out last week in a high-profile research report. He says the hack can be easily prevented.

The researchers demonstrated a novel way to access files that presumably were locked using Vista's BitLocker and similar disk encryption systems offered by competitors such as Apple. They showed it was possible to pilfer the encryption key needed to unlock the files by accessing a "ghost image" that remained in a computer's memory after the system entered hibernation mode. Ten minutes after machines were powered down, the researchers were still able to access the key by using compressed air to cool the memory chips.

According to Humphries, the hack is easily prevented. Users can configure BitLocker to prevent a PC from booting, or resuming from hibernation without confirmation of a password or a second key contained on a USB stick.

"The thing to keep in mind here is the old adage of balancing security, usability and risk," he wrote. "For example BitLocker provides several options that allow for a user (or more likely Administrator) to increase their security protections but at the cost of somewhat lowering ease-of-use."

He said BitLocker allows administrators to remotely change protection settings by having a script execute.

"Thanks to BitLocker's design, which implements key abstraction, a script can be executed that adds pre-boot protection mechanisms without requiring the re-encryption of the hard disk. This script can therefore execute very quickly.

Exotica

Humphries also worked to downplay the likelihood that an attack as exotic as this one would work in the trenches or real-world crime. Thieves would first have to get physical access to a machine and the machine would most likely need to be in sleep mode.

"I would posit that the opportunistic laptop thief is somewhat unlikely to carry a separate laptop on which they will have installed tools that allow them to reconstruct cryptographic keys - or for that matter have a can of compressed air handy."

The Bitlocker attack is a wake-up call for privacy and security buffs because it demonstrated a fundamental weakness in a key tool used to protect sensitive data. BitLocker, and a similar feature that Apple has baked into OS X called FileVault, allow users to encrypt selected files or entire hard drives. In the event a PC is lost or stolen, files containing trade secrets, employee data or other confidential information would be unreadable to anyone without the key.

According to the researchers, who came from Princeton University, Wind River System and the Electronic Frontier Foundation, there is little that can be done to prevent ghost images from being readily accessed. Software changes are likely to be ineffective, and altering the way hardware works inside a laptop would take years.

But as Humphries demonstrates, one or two additional measures could make all the difference. Question is, will anyone use them? ®

The Power of One eBook: Top reasons to choose HP BladeSystem

More from The Register

next story
HIDDEN packet sniffer spy tech in MILLIONS of iPhones, iPads – expert
Don't panic though – Apple's backdoor is not wide open to all, guru tells us
Mozilla fixes CRITICAL security holes in Firefox, urges v31 upgrade
Misc memory hazards 'could be exploited' - and guess what, one's a Javascript vuln
BMW's ConnectedDrive falls over, bosses blame upgrade snafu
Traffic flows up 20% as motorway middle lanes miraculously unclog
LibreSSL RNG bug fix: What's all the forking fuss about, ask devs
Blow to bit-spitter 'tis but a flesh wound, claim team
Manic malware Mayhem spreads through Linux, FreeBSD web servers
And how Google could cripple infection rate in a second
Yorkshire cops fail to grasp principle behind BT Fon Wi-Fi network
'Prevent people that are passing by to hook up to your network', pleads plod
Don't look, Snowden: Security biz chases Tails with zero-day flaws alert
Exodus vows not to sell secrets of whistleblower's favorite OS
Researcher sat on critical IE bugs for THREE YEARS
VUPEN waited for Pwn2Own cash while IE's sandbox leaked
prev story

Whitepapers

Top three mobile application threats
Prevent sensitive data leakage over insecure channels or stolen mobile devices.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Top 8 considerations to enable and simplify mobility
In this whitepaper learn how to successfully add mobile capabilities simply and cost effectively.
Application security programs and practises
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
The Essential Guide to IT Transformation
ServiceNow discusses three IT transformations that can help CIO's automate IT services to transform IT and the enterprise.