Debian DLA-1560-1 : gnutls28 security update

Medium Nessus Plugin ID 118504

Synopsis

The remote Debian host is missing a security update.

Description

A set of vulnerabilities was discovered in GnuTLS which allowed
attackers to do plain text recovery on TLS connections with certain
cipher types.

CVE-2018-10844

It was found that the GnuTLS implementation of HMAC-SHA-256 was
vulnerable to a Lucky thirteen style attack. Remote attackers could
use this flaw to conduct distinguishing attacks and plaintext-recovery
attacks via statistical analysis of timing data using crafted packets.

CVE-2018-10845

It was found that the GnuTLS implementation of HMAC-SHA-384 was
vulnerable to a Lucky thirteen style attack. Remote attackers could
use this flaw to conduct distinguishing attacks and plain text
recovery attacks via statistical analysis of timing data using crafted
packets.

CVE-2018-10846

A cache-based side channel in GnuTLS implementation that leads to
plain text recovery in cross-VM attack setting was found. An attacker
could use a combination of 'Just in Time' Prime+probe attack in
combination with Lucky-13 attack to recover plain text using crafted
packets.

For Debian 8 'Jessie', these problems have been fixed in version
3.3.30-0+deb8u1. It was found to be more practical to update to the
latest upstream version of the 3.3.x branch since upstream's fixes
were rather invasive and required cipher list changes anyways. This
will facilitate future LTS updates as well.

This change therefore also includes the following major policy
changes, as documented in the NEWS file :

- ARCFOUR (RC4) and SSL 3.0 are no longer included in the
default priorities list. Those have to be explicitly
enabled, e.g., with a string like 'NORMAL:+ARCFOUR-128'
or 'NORMAL:+VERS-SSL3.0', respectively.

- The ciphers utilizing HMAC-SHA384 and SHA256 have been
removed from the default priority strings. They are not
necessary for compatibility or other purpose and provide
no advantage over their SHA1 counter-parts, as they all
depend on the legacy TLS CBC block mode.

- Follow closely RFC5280 recommendations and use UTCTime
for dates prior to 2050.

- Require strict DER encoding for certificates, OCSP
requests, private keys, CRLs and certificate requests,
in order to reduce issues due to the complexity of BER
rules.

- Refuse to import v1 or v2 certificates that contain
extensions.

API and ABI compatibility is retained, however, although new symbols
have been added. Many bugfixes are also included in the upload. See
the provided upstream changelog for more details.

We recommend that you upgrade your gnutls28 packages and do not expect
significant breakage.

NOTE: Tenable Network Security has extracted the preceding description
block directly from the DLA security advisory. Tenable has attempted
to automatically clean and format it as much as possible without
introducing additional issues.

Solution

Upgrade the affected packages.

See Also

https://lists.debian.org/debian-lts-announce/2018/10/msg00022.html

https://packages.debian.org/source/jessie/gnutls28

Plugin Details

Severity: Medium

ID: 118504

File Name: debian_DLA-1560.nasl

Version: 1.2

Type: local

Agent: unix

Published: 2018/10/31

Modified: 2018/11/01

Dependencies: 12634

Risk Information

Risk Factor: Medium

CVSS v2.0

Base Score: 4.3

Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:N/A:N

CVSS v3.0

Base Score: 5.9

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Vulnerability Information

CPE: p-cpe:/a:debian:debian_linux:gnutls-bin, p-cpe:/a:debian:debian_linux:gnutls-doc, p-cpe:/a:debian:debian_linux:guile-gnutls, p-cpe:/a:debian:debian_linux:libgnutls-deb0-28, p-cpe:/a:debian:debian_linux:libgnutls-openssl27, p-cpe:/a:debian:debian_linux:libgnutls28-dbg, p-cpe:/a:debian:debian_linux:libgnutls28-dev, p-cpe:/a:debian:debian_linux:libgnutlsxx28, cpe:/o:debian:debian_linux:8.0

Patch Publication Date: 2018/10/30

Reference Information

CVE: CVE-2018-10844, CVE-2018-10845, CVE-2018-10846