CVE-2015-0837

The mpi_powm function in Libgcrypt before 1.6.3 and GnuPG before 1.4.19 allows attackers to obtain sensitive information by leveraging timing differences when accessing a pre-computed table during modular exponentiation, related to a "Last-Level Cache Side-Channel Attack."

Red Hat Product Security has rated this issue as having low security impact, a future update may address this flaw in the libgcrypt and gnupg2 packages.

The attack leading to this flaw, is difficult to conduct in practice especially for cross-vm environments, mainly because the attacker needs to run their timing attack script at the exact same time decryption runs on the victim machine. Also this is essentially a chosen ciphertext attack because the attacker provides the ciphertext which the victim needs to be decrypt. Such actions only work when there is sufficient social engineer involved.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.