FreeBSD VuXML: Documenting security issues in FreeBSD and the FreeBSD Ports Collection

gnupg -- side channel attack on RSA secret keys

Affected packages
gnupg < 1.4.14


VuXML ID 80771b89-f57b-11e2-bf21-b499baab0cbe
Discovery 2013-07-18
Entry 2013-07-25
Modified 2013-07-26

A Yarom and Falkner paper reports:

Flush+Reload is a cache side-channel attack that monitors access to data in shared pages. In this paper we demonstrate how to use the attack to extract private encryption keys from GnuPG. The high resolution and low noise of the Flush+Reload attack enables a spy program to recover over 98% of the bits of the private key in a single decryption or signing round. Unlike previous attacks, the attack targets the last level L3 cache. Consequently, the spy program and the victim do not need to share the execution core of the CPU. The attack is not limited to a traditional OS and can be used in a virtualised environment, where it can attack programs executing in a different VM.