Subject: [ASA-201709-14] lib32-libgcrypt: private key recovery

Arch Linux Security Advisory ASA-201709-14
==========================================

Severity: Medium
Date    : 2017-09-18
CVE-ID  : CVE-2017-0379
Package : lib32-libgcrypt
Type    : private key recovery
Remote  : No
Link    : https://security.archlinux.org/AVG-403

Summary
=======

The package lib32-libgcrypt before version 1.8.1-1 is vulnerable to
private key recovery.

Resolution
==========

Upgrade to 1.8.1-1.

# pacman -Syu "lib32-libgcrypt>=1.8.1-1"

The problem has been fixed upstream in version 1.8.1.

Workaround
==========

None.

Description
===========

Libgcrypt before 1.8.1 does not properly consider Curve25519 side-
channel attacks, which makes it easier for attackers to discover a
secret key, related to cipher/ecc.c and mpi/ec.c. On multi user systems
or on boxes with virtual machines this attack may be used to steal
private keys.

Impact
======

On a multi user system or on boxes with virtual machines a local
attacker may be able to perform a side-channel attack to steal private
keys.

References
==========

https://lists.gnupg.org/pipermail/gnupg-announce/2017q3/000414.html
https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commitdiff;h=bf76acbf0da6b0f245e491bec12c0f0a1b5be7c9
https://eprint.iacr.org/2017/806
https://security.archlinux.org/CVE-2017-0379