nettle: Information disclosure

Background

Nettle is a cryptographic library that is designed to fit easily in almost any context: In cryptographic toolkits for object-oriented languages, such as C++, Python, or Pike, in applications like lsh or GnuPG, or even in kernel space.

Description

It was found that nettle’s RSA and DSA decryption code was vulnerable to cache-related side channel attacks.

See the referenced technical paper “Cache Attacks Enable Bulk Key Recovery on the Cloud” below for details.

Impact

An attacker could recover the private key from a co-located virtual-machine instance.

Workaround

There is no known workaround at this time.

Resolution

All nettle users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=dev-libs/nettle-3.2-r1"