Libgcrypt: Side-channel attack

Background

Libgcrypt is a general purpose cryptographic library derived out of GnuPG.

Description

A vulnerability in the implementation of ElGamal decryption procedures of Libgcrypt leaks information to various side-channels.

Impact

A physical side-channel attack allows a remote attacker to fully extract decryption keys during the decryption of a chosen ciphertext.

Workaround

There is no known workaround at this time.

Resolution

All Libgcrypt users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=dev-libs/libgcrypt-1.5.4"