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("2.11");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/10/20");

  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:
"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).

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://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) 2016-2023 Canonical, Inc. / NASL script (C) 2016-2023 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 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)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : ubuntu_report_get()
  );
  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');
}