Ubuntu 7.04 / 7.10 / 8.04 LTS : openssh vulnerability (USN-612-2)

2013-03-09T00:00:00
ID UBUNTU_USN-612-2.NASL
Type nessus
Reporter Tenable
Modified 2018-11-28T00:00:00

Description

A weakness has been discovered in the random number generator used by OpenSSL on Debian and Ubuntu systems. As a result of this weakness, certain encryption keys are much more common than they should be, such that an attacker could guess the key through a brute-force attack given minimal knowledge of the system. This particularly affects the use of encryption keys in OpenSSH.

This vulnerability only affects operating systems which (like Ubuntu) are based on Debian. However, other systems can be indirectly affected if weak keys are imported into them.

We consider this an extremely serious vulnerability, and urge all users to act immediately to secure their systems.

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.

                                        
                                            #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-612-2. The text 
# itself is copyright (C) Canonical, Inc. See 
# <http://www.ubuntu.com/usn/>. Ubuntu(R) is a registered 
# trademark of Canonical, Inc.
#

include("compat.inc");

if (description)
{
  script_id(65109);
  script_version("1.7");
  script_cvs_date("Date: 2018/11/28 11:42:05");

  script_cve_id("CVE-2008-0166");
  script_bugtraq_id(29179);
  script_xref(name:"USN", value:"612-2");

  script_name(english:"Ubuntu 7.04 / 7.10 / 8.04 LTS : openssh vulnerability (USN-612-2)");
  script_summary(english:"Checks dpkg output for updated packages.");

  script_set_attribute(
    attribute:"synopsis", 
    value:
"The remote Ubuntu host is missing one or more security-related
patches."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"A weakness has been discovered in the random number generator used by
OpenSSL on Debian and Ubuntu systems. As a result of this weakness,
certain encryption keys are much more common than they should be, such
that an attacker could guess the key through a brute-force attack
given minimal knowledge of the system. This particularly affects the
use of encryption keys in OpenSSH.

This vulnerability only affects operating systems which (like Ubuntu)
are based on Debian. However, other systems can be indirectly affected
if weak keys are imported into them.

We consider this an extremely serious vulnerability, and urge all
users to act immediately to secure their systems.

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."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://usn.ubuntu.com/612-2/"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected openssh-client and / or openssh-server packages."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"exploit_framework_core", value:"true");
  script_cwe_id(310);

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:openssh-client");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:openssh-server");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:7.04");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:7.10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:8.04:-:lts");

  script_set_attribute(attribute:"patch_publication_date", value:"2008/05/13");
  script_set_attribute(attribute:"in_the_news", value:"true");
  script_set_attribute(attribute:"plugin_publication_date", value:"2013/03/09");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"Ubuntu Security Notice (C) 2013-2018 Canonical, Inc. / NASL script (C) 2018 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Ubuntu Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}


include("audit.inc");
include("ubuntu.inc");
include("misc_func.inc");

if ( ! get_kb_item("Host/local_checks_enabled") ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/Ubuntu/release");
if ( isnull(release) ) audit(AUDIT_OS_NOT, "Ubuntu");
release = chomp(release);
if (! ereg(pattern:"^(7\.04|7\.10|8\.04)$", string:release)) audit(AUDIT_OS_NOT, "Ubuntu 7.04 / 7.10 / 8.04", "Ubuntu " + release);
if ( ! get_kb_item("Host/Debian/dpkg-l") ) audit(AUDIT_PACKAGE_LIST_MISSING);

cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Ubuntu", cpu);

flag = 0;

if (ubuntu_check(osver:"7.04", pkgname:"openssh-client", pkgver:"1:4.3p2-8ubuntu1.3")) flag++;
if (ubuntu_check(osver:"7.04", pkgname:"openssh-server", pkgver:"1:4.3p2-8ubuntu1.3")) flag++;
if (ubuntu_check(osver:"7.10", pkgname:"openssh-client", pkgver:"1:4.6p1-5ubuntu0.3")) flag++;
if (ubuntu_check(osver:"7.10", pkgname:"openssh-server", pkgver:"1:4.6p1-5ubuntu0.3")) flag++;
if (ubuntu_check(osver:"8.04", pkgname:"openssh-client", pkgver:"1:4.7p1-8ubuntu1.1")) flag++;
if (ubuntu_check(osver:"8.04", pkgname:"openssh-server", pkgver:"1:4.7p1-8ubuntu1.1")) flag++;

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : ubuntu_report_get()
  );
  exit(0);
}
else
{
  tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "openssh-client / openssh-server");
}