libgnutls in GnuTLS before 2.8.2 does not properly handle a '\0' character in a domain name in the subject's (1) Common Name (CN) or (2) Subject Alternative Name (SAN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority.

The remote Oracle Linux 5 host has packages installed that are affected by a vulnerability as referenced in the ELSA-2009-1232 advisory.

    [1.4.1-3.5]
    - fix NUL characters in DN and SAN cert fields issue,       make sure gnutls_x509_crt_check_hostname() fails when certificate       has no CN or SAN CVE-2009-2730 (#516231)

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

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

CVE-2009-2730 gnutls: incorrect verification of SSL certificate with NUL in name (GNUTLS-SA-2009-4)

A flaw was discovered in the way GnuTLS handles NULL characters in certain fields of X.509 certificates. If an attacker is able to get a carefully-crafted certificate signed by a Certificate Authority trusted by an application using GnuTLS, the attacker could use the certificate during a man-in-the-middle attack and potentially confuse the application into accepting it by mistake. (CVE-2009-2730)

The remote host is affected by the vulnerability described in GLSA-201206-18 (GnuTLS: Multiple vulnerabilities)

    Multiple vulnerabilities have been found in GnuTLS:
      An error in libgnutls does not properly sanitize '\\0' characters from         certificate fields (CVE-2009-2730).
      An error in the TLS and SSL protocols mistreats renegotiation         handshakes (CVE-2009-3555).
      A boundary error in the 'gnutls_session_get_data()' function in         gnutls_session.c could cause a buffer overflow (CVE-2011-4128).
      An error in the '_gnutls_ciphertext2compressed()' function in         gnutls_cipher.c could cause memory corruption (CVE-2012-1573).
  Impact :

    A remote attacker could perform man-in-the-middle attacks to spoof       arbitrary SSL servers or cause a Denial of Service condition in       applications linked against GnuTLS.
  Workaround :

    There is no known workaround at this time.

The remote host is affected by the vulnerability described in GLSA-201110-05 (GnuTLS: Multiple vulnerabilities)

    Multiple vulnerabilities have been discovered in GnuTLS. Please review       the CVE identifiers referenced below for details.
  Impact :

    An attacker could perform man-in-the-middle attacks to spoof arbitrary       SSL servers via a crafted certificate issued by a legitimate       Certification Authority or to inject an arbitrary amount of chosen       plaintext into the beginning of the application protocol stream, allowing       for further exploitation.
  Workaround :

    There is no known workaround at this time.

Dan Kaminsky and Moxie Marlinspike discovered that gnutls, an implementation of the TLS/SSL protocol, does not properly handle a '\0' character in a domain name in the subject's Common Name or Subject Alternative Name (SAN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority.
(CVE-2009-2730 )

In addition, with this update, certificates with MD2 hash signatures are no longer accepted since they're no longer considered cryptograhically secure. It only affects the oldstable distribution (etch).(CVE-2009-2409 )

gnutls did not properly handle embedded '\0' characters in x509 certificates. Attackers using specially crafted certificates could exploit that to conduct man-in-the-middle attacks (CVE-2009-2730).

Multiple vulnerabilities has been found and corrected in gnutls :

gnutls-cli in GnuTLS before 2.6.6 does not verify the activation and expiration times of X.509 certificates, which allows remote attackers to successfully present a certificate that is (1) not yet valid or (2) no longer valid, related to lack of time checks in the
_gnutls_x509_verify_certificate function in lib/x509/verify.c in libgnutls_x509, as used by (a) Exim, (b) OpenLDAP, and (c) libsoup (CVE-2009-1417).

A vulnerability have been discovered and corrected in GnuTLS before 2.8.2, which could allow man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority (CVE-2009-2730).

Packages for 2008.0 are provided for Corporate Desktop 2008.0 customers

This update fixes this vulnerability.

New gnutls packages are available for Slackware 12.1, 12.2, 13.0, and
-current to fix a security issue.

This update of gnutls improves the verification of the domain/subject names in SSL certificates (CVE-2009-2730).

This update fixes handling of NUL characters in certificate Common Name or subjectAltName fields especially in regards to comparsion to hostnames.

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

This update of gnutls improves the verification of the domain/subject names in a SSL certificate. CVE-2009-2730 has been assigned to this issue.

This update of GnuTLS improves the verification of the domain/subject names in a SSL certificate. CVE-2009-2730 has been assigned to this issue.

Updated gnutls packages that fix a security issue are now available for Red Hat Enterprise Linux 4 and 5.

This update has been rated as having moderate security impact by the Red Hat Security Response Team.

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

A flaw was discovered in the way GnuTLS handles NULL characters in certain fields of X.509 certificates. If an attacker is able to get a carefully-crafted certificate signed by a Certificate Authority trusted by an application using GnuTLS, the attacker could use the certificate during a man-in-the-middle attack and potentially confuse the application into accepting it by mistake. (CVE-2009-2730)

Users of GnuTLS are advised to upgrade to these updated packages, which contain a backported patch that corrects this issue.

A vulnerability have been discovered and corrected in GnuTLS before 2.8.2, which could allow man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority (CVE-2009-2730).

This update fixes this vulnerability.

GnuTLS reports :

By using a NUL byte in CN/SAN fields, it was possible to fool GnuTLS into 1) not printing the entire CN/SAN field value when printing a certificate and 2) cause incorrect positive matches when matching a hostname against a certificate.

Moxie Marlinspike and Dan Kaminsky independently discovered that GnuTLS did not properly handle certificates with NULL characters in the certificate name. An attacker could exploit this to perform a man in the middle attack to view sensitive information or alter encrypted communications. (CVE-2009-2730)

Dan Kaminsky discovered GnuTLS would still accept certificates with MD2 hash signatures. As a result, an attacker could potentially create a malicious trusted certificate to impersonate another site. This issue only affected Ubuntu 6.06 LTS and Ubuntu 8.10. (CVE-2009-2409)

USN-678-1 fixed a vulnerability and USN-678-2 a regression in GnuTLS.
The upstream patches introduced a regression when validating certain certificate chains that would report valid certificates as untrusted.
This update fixes the problem, and only affected Ubuntu 6.06 LTS and Ubuntu 8.10 (Ubuntu 8.04 LTS and 9.04 were fixed at an earlier date).
In an effort to maintain a strong security stance and address all known regressions, this update deprecates X.509 validation chains using MD2 and MD5 signatures. To accomodate sites which must still use a deprected RSA-MD5 certificate, GnuTLS has been updated to stop looking when it has found a trusted intermediary certificate. This new handling of intermediary certificates is in accordance with other SSL implementations.

Martin von Gagern discovered that GnuTLS did not properly verify certificate chains when the last certificate in the chain was self-signed. If a remote attacker were able to perform a man-in-the-middle attack, this flaw could be exploited to view sensitive information. (CVE-2008-4989).

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

ID	Name	Product	Family	Severity
67916	Oracle Linux 5 : gnutls (ELSA-2009-1232)	Nessus	Oracle Linux Local Security Checks	medium
60647	Scientific Linux Security Update : gnutls on SL4.x, SL5.x i386/x86_64	Nessus	Scientific Linux Local Security Checks	high
59671	GLSA-201206-18 : GnuTLS: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	high
56458	GLSA-201110-05 : GnuTLS: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	high
44800	Debian DSA-1935-1 : gnutls13 gnutls26 - several vulnerabilities	Nessus	Debian Local Security Checks	high
44618	openSUSE Security Update : gnutls (gnutls-1938)	Nessus	SuSE Local Security Checks	high
42994	Mandriva Linux Security Advisory : gnutls (MDVSA-2009:308)	Nessus	Mandriva Local Security Checks	high
42168	Slackware 12.1 / 12.2 / 13.0 / current : gnutls (SSA:2009-290-01)	Nessus	Slackware Local Security Checks	high
42002	openSUSE 10 Security Update : gnutls (gnutls-6471)	Nessus	SuSE Local Security Checks	high
41629	Fedora 10 : gnutls-2.4.2-5.fc10 (2009-8622)	Nessus	Fedora Local Security Checks	high
41628	Fedora 11 : gnutls-2.6.6-3.fc11 (2009-8565)	Nessus	Fedora Local Security Checks	high
41399	SuSE 11 Security Update : GnuTLS (SAT Patch Number 1260)	Nessus	SuSE Local Security Checks	high
41323	SuSE9 Security Update : GnuTLS (YOU Patch Number 12501)	Nessus	SuSE Local Security Checks	high
40904	openSUSE Security Update : gnutls (gnutls-1259)	Nessus	SuSE Local Security Checks	high
40903	openSUSE Security Update : gnutls (gnutls-1259)	Nessus	SuSE Local Security Checks	high
40782	RHEL 4 / 5 : gnutls (RHSA-2009:1232)	Nessus	Red Hat Local Security Checks	high
40779	CentOS 4 / 5 : gnutls (CESA-2009:1232)	Nessus	CentOS Local Security Checks	high
40695	Mandriva Linux Security Advisory : gnutls (MDVSA-2009:210)	Nessus	Mandriva Local Security Checks	high
40659	FreeBSD : GnuTLS -- improper SSL certificate verification (856a6f84-8b30-11de-8062-00e0815b8da8)	Nessus	FreeBSD Local Security Checks	high
40656	Ubuntu 6.06 LTS / 8.04 LTS / 8.10 / 9.04 : gnutls12, gnutls13, gnutls26 vulnerabilities (USN-809-1)	Nessus	Ubuntu Local Security Checks	high

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