Vigil@nce - GnuPG: key detection by LLC cache
March 2015 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
An attacker, who is located in a virtual machine of a computer
performing operations with GnuPG on chosen messages, can analyze
the LLC of this computer, in order to guess a decryption key.
Impacted products: GnuPG
Severity: 1/4
Creation date: 02/03/2015
DESCRIPTION OF THE VULNERABILITY
The GnuPG product implements the modular exponentiation used by
the RSA algorithm.
The LLC (Last Level Cache) cache can be shared between several
cores of a processor. It can for example contain operations of
other virtual machines.
However, during a modular exponentiation operation, a local
attacker can analyze the LLC, to deduce the decryption key.
An attacker, who is located in a virtual machine of a computer
performing operations with GnuPG on chosen messages, can therefore
analyze the LLC of this computer, in order to guess a decryption
key.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/GnuPG-key-detection-by-LLC-cache-16285