On Thu, Jul 10, 2003 at 04:45:58PM +0200, Thomas Shaddack wrote:
On Wed, 9 Jul 2003, Eric Murray wrote:
I doubt it as well. DRAM also has power-off memory persistence and nearly everyone in security ignores that as well.
But not the spooks :
"The FEI-374i-DRS is a data recovery system that captures and preserved digital data, in its original format, directly from the Dynamic Random Access Memory (DRAM) of Digital Telephone Answering Machines (DTAMs) .. The FEI-374i-DRS is an indispensable tool for forensic investigators required to evaluate residual audio and tag information retained in today's DRAM-based DTAMs."
The system doesn't seem to be able to recover data from powered-off DRAM.
[..] It's still interesting.
It is impossible to get access to the voltage on the DRAM cell capacitors (at least if the chip is in its case and we can access only its pins). We can only see if it is in the range for H or L. And after a power-down (or even a sufficiently long period without a refresh of the given cell) the cell capacitor loses voltage steadily, reaching the level of L (or maybe H?) within at most couple seconds.
I would not bet on that for sensitive data. See Peter Gutmans and Ross Anderson's papers on RAM memory remanance. Eric