Updated gnutls packages that fix three security issues and one bug are now available for Red Hat Enterprise Linux 6.

Red Hat Product Security has rated this update as having Moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

The GnuTLS library provides support for cryptographic algorithms and for protocols such as Transport Layer Security (TLS).

It was found that GnuTLS did not check activation and expiration dates of CA certificates. This could cause an application using GnuTLS to incorrectly accept a certificate as valid when its issuing CA is already expired. (CVE-2014-8155)

It was found that GnuTLS did not verify whether a hashing algorithm listed in a signature matched the hashing algorithm listed in the certificate. An attacker could create a certificate that used a different hashing algorithm than it claimed, possibly causing GnuTLS to use an insecure, disallowed hashing algorithm during certificate verification. (CVE-2015-0282)

It was discovered that GnuTLS did not check if all sections of X.509 certificates indicate the same signature algorithm. This flaw, in combination with a different flaw, could possibly lead to a bypass of the certificate signature check. (CVE-2015-0294)

The CVE-2014-8155 issue was discovered by Marcel Kolaja of Red Hat.
The CVE-2015-0282 and CVE-2015-0294 issues were discovered by Nikos Mavrogiannopoulos of the Red Hat Security Technologies Team.

This update also fixes the following bug :

* Previously, under certain circumstances, the certtool utility could generate X.509 certificates which contained a negative modulus.
Consequently, such certificates could have interoperation problems with the software using them. The bug has been fixed, and certtool no longer generates X.509 certificates containing a negative modulus.
(BZ#1036385)

Users of gnutls are advised to upgrade to these updated packages, which contain backported patches to correct these issues.

The remote Ubuntu 14.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-2540-1 advisory.

    It was discovered that GnuTLS did not perform date and time checks on CA certificates, contrary to     expectations. This issue only affected Ubuntu 10.04 LTS. (CVE-2014-8155)

    Nikos Mavrogiannopoulos discovered that GnuTLS incorrectly verified that signature algorithms matched. A     remote attacker could possibly use this issue to downgrade to a disallowed algorithm. This issue only     affected Ubuntu 10.04 LTS, Ubuntu 12.04 LTS and Ubuntu 14.04 LTS. (CVE-2015-0282)

    It was discovered that GnuTLS incorrectly verified certificate algorithms. A remote attacker could     possibly use this issue to downgrade to a disallowed algorithm. (CVE-2015-0294)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Oracle Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2015-1457 advisory.

    - fix CVE-2015-0282 (#1198159)
    - fix CVE-2015-0294 (#1198159)

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Multiple vulnerabilities have been discovered in GnuTLS, a library implementing the TLS and SSL protocols. The Common Vulnerabilities and Exposures project identifies the following problems :

CVE-2014-8155

Missing date/time checks on CA certificates

CVE-2015-0282

GnuTLS does not verify the RSA PKCS #1 signature algorithm to match the signature algorithm in the certificate, leading to a potential downgrade to a disallowed algorithm without detecting it.

CVE-2015-0294

GnuTLS does not check whether the two signature algorithms match on certificate import.

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.

It was found that GnuTLS did not check activation and expiration dates of CA certificates. This could cause an application using GnuTLS to incorrectly accept a certificate as valid when its issuing CA is already expired. (CVE-2014-8155)

It was found that GnuTLS did not verify whether a hashing algorithm listed in a signature matched the hashing algorithm listed in the certificate. An attacker could create a certificate that used a different hashing algorithm than it claimed, possibly causing GnuTLS to use an insecure, disallowed hashing algorithm during certificate verification. (CVE-2015-0282)

It was discovered that GnuTLS did not check if all sections of X.509 certificates indicate the same signature algorithm. This flaw, in combination with a different flaw, could possibly lead to a bypass of the certificate signature check. (CVE-2015-0294)

The CVE-2014-8155 issue was discovered by Marcel Kolaja of Red Hat.
The CVE-2015-0282 and CVE-2015-0294 issues were discovered by Nikos Mavrogiannopoulos of the Red Hat Security Technologies Team.

This update also fixes the following bug :

  - Previously, under certain circumstances, the certtool     utility could generate X.509 certificates which     contained a negative modulus. Consequently, such     certificates could have interoperation problems with the     software using them. The bug has been fixed, and     certtool no longer generates X.509 certificates     containing a negative modulus.

GnuTLS before 2.9.10 does not verify the activation and expiration dates of CA certificates, which allows man-in-the-middle attackers to spoof servers via a certificate issued by a CA certificate that is (1) not yet valid or (2) no longer valid. (CVE-2014-8155)

Impact

GnuTLS does not check activation and expiration dates of CA certificates. This can cause an application using GnuTLS to incorrectly accept a certificate as valid when its issuing CA is already expired.

GnuTLS was updated to fix two security issues :

  - A certificate algorithm consistency checking issue was     fixed, where GnuTLS did not check whether the two     signature algorithms match on certificate import. This     problem is not deemed to be exploitable currently.
    (CVE-2015-0294)

  - GNUTLS-SA-2015-1: GnuTLS did not verify the RSA PKCS #1     signature algorithm to match the signature algorithm in     the certificate, leading to a potential downgrade to a     disallowed algorithm, such as MD5, without detecting it.
    (CVE-2015-0282)

It was found that GnuTLS did not check activation and expiration dates of CA certificates. This could cause an application using GnuTLS to incorrectly accept a certificate as valid when its issuing CA is already expired. (CVE-2014-8155)

It was found that GnuTLS did not verify whether a hashing algorithm listed in a signature matched the hashing algorithm listed in the certificate. An attacker could create a certificate that used a different hashing algorithm than it claimed, possibly causing GnuTLS to use an insecure, disallowed hashing algorithm during certificate verification. (CVE-2015-0282)

It was discovered that GnuTLS did not check if all sections of X.509 certificates indicate the same signature algorithm. This flaw, in combination with a different flaw, could possibly lead to a bypass of the certificate signature check. (CVE-2015-0294)

The remote Redhat Enterprise Linux 5 host has one or more packages installed that are affected by multiple vulnerabilities that have been acknowledged by the vendor but will not be patched.

  - gnutls: Heap read overflow in read-packet.c (CVE-2017-5337)

  - The TLS protocol 1.2 and earlier, as used in Mozilla Firefox, Google Chrome, Qt, and other products, can     encrypt compressed data without properly obfuscating the length of the unencrypted data, which allows man-     in-the-middle attackers to obtain plaintext HTTP headers by observing length differences during a series     of guesses in which a string in an HTTP request potentially matches an unknown string in an HTTP header,     aka a CRIME attack. (CVE-2012-4929)

  - GnuTLS before 2.9.10 does not verify the activation and expiration dates of CA certificates, which allows     man-in-the-middle attackers to spoof servers via a certificate issued by a CA certificate that is (1) not     yet valid or (2) no longer valid. (CVE-2014-8155)

Note that Nessus has not tested for these issues but has instead relied on the package manager's report that the package is installed.

ID	Name	Product	Family	Published	Updated	Severity
85023	CentOS 6 : gnutls (CESA-2015:1457)	Nessus	CentOS Local Security Checks	7/28/2015	1/4/2021	high
82024	Ubuntu 14.04 LTS : GnuTLS vulnerabilities (USN-2540-1)	Nessus	Ubuntu Local Security Checks	3/24/2015	8/28/2024	high
85109	Oracle Linux 6 : gnutls (ELSA-2015-1457)	Nessus	Oracle Linux Local Security Checks	7/30/2015	10/22/2024	high
84949	RHEL 6 : gnutls (RHSA-2015:1457)	Nessus	Red Hat Local Security Checks	7/23/2015	2/5/2021	high
82166	Debian DLA-180-1 : gnutls26 security update	Nessus	Debian Local Security Checks	3/26/2015	1/11/2021	high
85193	Scientific Linux Security Update : gnutls on SL6.x i386/x86_64 (20150722)	Nessus	Scientific Linux Local Security Checks	8/4/2015	1/14/2021	high
123837	F5 Networks BIG-IP : GnuTLS vulnerability (K53330207)	Nessus	F5 Networks Local Security Checks	4/9/2019	11/2/2023	medium
82639	SuSE 11.3 Security Update : GnuTLS (SAT Patch Number 10536)	Nessus	SuSE Local Security Checks	4/8/2015	1/6/2021	medium
85230	Amazon Linux AMI : gnutls (ALAS-2015-575)	Nessus	Amazon Linux Local Security Checks	8/5/2015	2/3/2020	high
198427	RHEL 5 : gnutls (Unpatched Vulnerability)	Nessus	Red Hat Local Security Checks	6/3/2024	6/3/2024	critical

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