Ubuntu 14.04 LTS / 16.04 LTS : libxml2 vulnerabilities (USN-2994-1)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-2994-1. 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(91499);
  script_version("2.12");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/08/27");

  script_cve_id(
    "CVE-2015-8806",
    "CVE-2016-1762",
    "CVE-2016-1833",
    "CVE-2016-1834",
    "CVE-2016-1835",
    "CVE-2016-1836",
    "CVE-2016-1837",
    "CVE-2016-1838",
    "CVE-2016-1839",
    "CVE-2016-1840",
    "CVE-2016-2073",
    "CVE-2016-3627",
    "CVE-2016-3705",
    "CVE-2016-4447",
    "CVE-2016-4449",
    "CVE-2016-4483"
  );
  script_xref(name:"USN", value:"2994-1");

  script_name(english:"Ubuntu 14.04 LTS / 16.04 LTS : libxml2 vulnerabilities (USN-2994-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 14.04 LTS / 16.04 LTS host has packages installed that are affected by multiple vulnerabilities as
referenced in the USN-2994-1 advisory.

    It was discovered that libxml2 incorrectly handled certain malformed documents. If a user or automated
    system were tricked into opening a specially crafted document, an attacker could possibly cause libxml2 to
    crash, resulting in a denial of service. (CVE-2015-8806, CVE-2016-2073, CVE-2016-3627, CVE-2016-3705,
    CVE-2016-4447)

    It was discovered that libxml2 incorrectly handled certain malformed documents. If a user or automated
    system were tricked into opening a specially crafted document, an attacker could cause libxml2 to crash,
    resulting in a denial of service, or possibly execute arbitrary code. (CVE-2016-1762, CVE-2016-1834)

    Mateusz Jurczyk discovered that libxml2 incorrectly handled certain malformed documents. If a user or
    automated system were tricked into opening a specially crafted document, an attacker could cause libxml2
    to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2016-1833,
    CVE-2016-1838, CVE-2016-1839)

    Wei Lei and Liu Yang discovered that libxml2 incorrectly handled certain malformed documents. If a user or
    automated system were tricked into opening a specially crafted document, an attacker could cause libxml2
    to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2016-1835,
    CVE-2016-1837)

    Wei Lei and Liu Yang discovered that libxml2 incorrectly handled certain malformed documents. If a user or
    automated system were tricked into opening a specially crafted document, an attacker could cause libxml2
    to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only applied to
    Ubuntu 14.04 LTS, Ubuntu 15.10 and Ubuntu 16.04 LTS. (CVE-2016-1836)

    Kostya Serebryany discovered that libxml2 incorrectly handled certain malformed documents. If a user or
    automated system were tricked into opening a specially crafted document, an attacker could cause libxml2
    to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2016-1840)

    It was discovered that libxml2 would load certain XML external entities. If a user or automated system
    were tricked into opening a specially crafted document, an attacker could possibly obtain access to
    arbitrary files or cause resource consumption. (CVE-2016-4449)

    Gustavo Grieco discovered that libxml2 incorrectly handled certain malformed documents. If a user or
    automated system were tricked into opening a specially crafted document, an attacker could possibly cause
    libxml2 to crash, resulting in a denial of service. (CVE-2016-4483)

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.");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/notices/USN-2994-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2016-1834");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2016-1835");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2016/02/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2016/06/06");
  script_set_attribute(attribute:"plugin_publication_date", value:"2016/06/07");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libxml2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libxml2-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libxml2-udeb");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libxml2-utils");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python-libxml2");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:14.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:lts");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Ubuntu Local Security Checks");

  script_copyright(english:"Ubuntu Security Notice (C) 2016-2024 Canonical, Inc. / NASL script (C) 2016-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");

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

  exit(0);
}

include('debian_package.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/Ubuntu/release');
if ( isnull(os_release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
os_release = chomp(os_release);
if (! ('14.04' >< os_release || '16.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 14.04 / 16.04', 'Ubuntu ' + os_release);
if ( ! get_kb_item('Host/Debian/dpkg-l') ) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Ubuntu', cpu);

var pkgs = [
    {'osver': '14.04', 'pkgname': 'libxml2', 'pkgver': '2.9.1+dfsg1-3ubuntu4.8'},
    {'osver': '14.04', 'pkgname': 'libxml2-dev', 'pkgver': '2.9.1+dfsg1-3ubuntu4.8'},
    {'osver': '14.04', 'pkgname': 'libxml2-udeb', 'pkgver': '2.9.1+dfsg1-3ubuntu4.8'},
    {'osver': '14.04', 'pkgname': 'libxml2-utils', 'pkgver': '2.9.1+dfsg1-3ubuntu4.8'},
    {'osver': '14.04', 'pkgname': 'python-libxml2', 'pkgver': '2.9.1+dfsg1-3ubuntu4.8'},
    {'osver': '16.04', 'pkgname': 'libxml2', 'pkgver': '2.9.3+dfsg1-1ubuntu0.1'},
    {'osver': '16.04', 'pkgname': 'libxml2-dev', 'pkgver': '2.9.3+dfsg1-1ubuntu0.1'},
    {'osver': '16.04', 'pkgname': 'libxml2-udeb', 'pkgver': '2.9.3+dfsg1-1ubuntu0.1'},
    {'osver': '16.04', 'pkgname': 'libxml2-utils', 'pkgver': '2.9.3+dfsg1-1ubuntu0.1'},
    {'osver': '16.04', 'pkgname': 'python-libxml2', 'pkgver': '2.9.3+dfsg1-1ubuntu0.1'}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var osver = NULL;
  var pkgname = NULL;
  var pkgver = NULL;
  if (!empty_or_null(package_array['osver'])) osver = package_array['osver'];
  if (!empty_or_null(package_array['pkgname'])) pkgname = package_array['pkgname'];
  if (!empty_or_null(package_array['pkgver'])) pkgver = package_array['pkgver'];
  if (osver && pkgname && pkgver) {
    if (ubuntu_check(osver:osver, pkgname:pkgname, pkgver:pkgver)) flag++;
  }
}

if (flag)
{
  var extra = '';
  extra += ubuntu_report_get();
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : extra
  );
  exit(0);
}
else
{
  var tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'libxml2 / libxml2-dev / libxml2-udeb / libxml2-utils / etc');
}