public now.

http://lists.gnupg.org/pipermail/gnupg-announce/2013q4/000337.html

CVE-2013-4576 has been assigned to this security bug.

The paper describes two attacks.  The first attack allows to distinguish
keys: An attacker is able to notice which key is currently used for
decryption.  This is in general not a problem but may be used to reveal
the information that a message, encrypted to a commonly not used key,
has been received by the targeted machine.  We do not have a software
solution to mitigate this attack.

The second attack is more serious.  It is an adaptive chosen ciphertext
attack to reveal the private key.  A possible scenario is that the
attacker places a sensor (for example a standard smartphone) in the
vicinity of the targeted machine.  That machine is assumed to do
unattended RSA decryption of received mails, for example by using a mail
client which speeds up browsing by opportunistically decrypting mails
expected to be read soon.  While listening to the acoustic emanations of
the targeted machine, the smartphone will send new encrypted messages to
that machine and re-construct the private key bit by bit.  A 4096 bit
RSA key used on a laptop can be revealed within an hour.

GnuPG 1.4.16 avoids this attack by employing RSA blinding during
decryption.  GnuPG 2.x and current Gpg4win versions make use of
Libgcrypt which employs RSA blinding anyway and are thus not vulnerable.

For the highly interesting research on acoustic cryptanalysis and the
details of the attack see http://www.cs.tau.ac.il/~tromer/acoustic/ .

Update released for: gpg
Products:
SUSE-CORE 9-SP3-TERADATA (x86_64)

Update released for: gpg, gpg-debuginfo
Products:
SLE-SERVER 10-SP3-TERADATA (x86_64)

*** Bug 856440 has been marked as a duplicate of this bug. ***

gpg2 is unaffected (sle10 and later)

(an ltss update for sle10 might be considered at some point)