Lest we remember: Cold boot attacks on encryption keys

J. Alex Halderman, Seth D. Schoen, Nadia Heninger, William Clarkson, William Paul, Joseph A. Calandrino, Ariel J. Feldman, Jacob Appelbaum, Edward W. Felten

Research output: Contribution to conferencePaper

379 Scopus citations

Abstract

Contrary to popular assumption, DRAMs used in most modern computers retain their contents for several seconds after power is lost, even at room temperature and even if removed from a motherboard. Although DRAMs become less reliable when they are not refreshed, they are not immediately erased, and their contents persist sufficiently for malicious (or forensic) acquisition of usable full-system memory images. We show that this phenomenon limits the ability of an operating system to protect cryptographic key material from an attacker with physical access. We use cold reboots to mount successful attacks on popular disk encryption systems using no special devices or materials. We experimentally characterize the extent and predictability of memory remanence and report that remanence times can be increased dramatically with simple cooling techniques. We offer new algorithms for finding cryptographic keys in memory images and for correcting errors caused by bit decay. Though we discuss several strategies for partially mitigating these risks, we know of no simple remedy that would eliminate them.

Original languageEnglish (US)
Pages45-58
Number of pages14
StatePublished - Jan 1 2008
Event17th USENIX Security Symposium - San Jose, United States
Duration: Jul 28 2008Aug 1 2008

Conference

Conference17th USENIX Security Symposium
CountryUnited States
CitySan Jose
Period7/28/088/1/08

All Science Journal Classification (ASJC) codes

  • Computer Networks and Communications
  • Information Systems
  • Safety, Risk, Reliability and Quality

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    Alex Halderman, J., Schoen, S. D., Heninger, N., Clarkson, W., Paul, W., Calandrino, J. A., Feldman, A. J., Appelbaum, J., & Felten, E. W. (2008). Lest we remember: Cold boot attacks on encryption keys. 45-58. Paper presented at 17th USENIX Security Symposium, San Jose, United States.