Feeds

Security boffins attempt to freeze out cold boot crypto attack

Cache from chaos

Protecting users from Firesheep and other Sidejacking attacks with SSL

Security researchers have developed prototype countermeasures to defend against the recently developed cold boot crypto attack.

Cold boot is a technique for snatching cryptographic keys from memory, creating a means to circumvent disk encryption. A targeted machine that's been left hibernating would be turned off and quickly rebooted using an external hard drive, loaded with customised software, in order to extract encryption keys stored in memory.

The technique works because DRAM circuits used in modern PCs retain data for a short time after they are powered down, contrary to popular opinion. Cold boot attacks are of potential interest to both hackers and computer forensics experts.

Crypto boffins are on the way to defending against the attack. By saving cryptographic keys in CPU cache, instead of potentially vulnerable DRAM, the attack can potentially be frustrated.

"By switching the cache into a special mode one can force that data remains in the cache and is not written to the backing RAM locations," write the security researchers behind the Frozen Cache blog. "Thus, the encryption key can't be extracted from RAM. This technique is actually not new: LinuxBIOS/CoreBoot calls this Cache-as-RAM. They use it to allow "RAM access", even before the memory controller is initialized."

The researchers have developed a proof-of-concept implementation of the defence that works under Linux but many problems remain, particularly in recovering from hibernation.

"Disabling/freezing the CPU's cache severely degrades the performance," the researchers write.

"However, this seems acceptable if one considers that this special mode only needs to be set whenever the screen is locked (all efforts are pretty much worthless if an unlocked laptop is stolen). A very first proof-of-concept test on Linux shows that there's quite a bit of performance optimization necessary to make even just the act of unlocking the GUI an acceptable experience (from a performance/usability perspective)."

Other factors, such as developing an approach for machines with multi-core CPUs, as well as optimisation (fine-tweaking) problems remain to be addressed. Interested parties can follow the evolution of the idea through the Frozen Cache blog here. ®

The next step in data security

More from The Register

next story
Israeli spies rebel over mass-snooping on innocent Palestinians
'Disciplinary treatment will be sharp and clear' vow spy-chiefs
Infosec geniuses hack a Canon PRINTER and install DOOM
Internet of Stuff securo-cockups strike yet again
'Speargun' program is fantasy, says cable operator
We just might notice if you cut our cables
Apple Pay is a tidy payday for Apple with 0.15% cut, sources say
Cupertino slurps 15 cents from every $100 purchase
YouTube, Amazon and Yahoo! caught in malvertising mess
Cisco says 'Kyle and Stan' attack is spreading through compromised ad networks
Hackers pop Brazil newspaper to root home routers
Step One: try default passwords. Step Two: Repeat Step One until success
Greater dev access to iOS 8 will put us AT RISK from HACKERS
Knocking holes in Apple's walled garden could backfire, says securo-chap
Microsoft to patch ASP.NET mess even if you don't
We know what's good for you, because we made the mess says Redmond
prev story

Whitepapers

Providing a secure and efficient Helpdesk
A single remote control platform for user support is be key to providing an efficient helpdesk. Retain full control over the way in which screen and keystroke data is transmitted.
Saudi Petroleum chooses Tegile storage solution
A storage solution that addresses company growth and performance for business-critical applications of caseware archive and search along with other key operational systems.
Security and trust: The backbone of doing business over the internet
Explores the current state of website security and the contributions Symantec is making to help organizations protect critical data and build trust with customers.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.