From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glynn Clements Subject: Re: Protect against cold boot attacks? Date: Thu, 24 Nov 2011 20:45:20 +0000 Message-ID: <20174.44256.195550.595437@cerise.gclements.plus.com> References: Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-admin-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: "Fred ." Cc: linux-admin@vger.kernel.org Fred . wrote: > Will > su-c 'sync; echo 3 > /proc/sys/vm/drop_caches' > protect against cold boot attacks? No. Writing to drop_caches releases the memory for subsequent re-use; it doesn't overwrite it, so anything stored in that memory is still susceptible to a cold-boot attack. > Is there anything that will protect against cold boot attacks? Physical security. Other than that, it's a matter of degree. Particularly sensitive information (passwords, encryption keys) should be overwritten by the application once they are no longer required. Larger amounts of application data (i.e. documents) can't really avoid being held in RAM. -- Glynn Clements