Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS : lxml vulnerability (USN-3841-1)

2018-12-11T00:00:00
ID UBUNTU_USN-3841-1.NASL
Type nessus
Reporter Ubuntu Security Notice (C) 2018-2020 Canonical, Inc. / NASL script (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
Modified 2020-04-28T00:00:00

Description

It was discovered that lxml incorrectly handled certain HTML files. An attacker could possibly use this issue to conduct cross-site scripting (XSS) attacks.

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-3841-1. 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(119580);
  script_version("1.6");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/04/28");

  script_cve_id("CVE-2018-19787");
  script_xref(name:"USN", value:"3841-1");

  script_name(english:"Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS : lxml vulnerability (USN-3841-1)");
  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:
"It was discovered that lxml incorrectly handled certain HTML files. An
attacker could possibly use this issue to conduct cross-site scripting
(XSS) attacks.

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/3841-1/"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected python-lxml and / or python3-lxml packages."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python-lxml");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python3-lxml");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:14.04");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");

  script_set_attribute(attribute:"vuln_publication_date", value:"2018/12/02");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/12/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/12/11");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"Ubuntu Security Notice (C) 2018-2020 Canonical, Inc. / NASL script (C) 2018-2020 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 (! preg(pattern:"^(14\.04|16\.04|18\.04)$", string:release)) audit(AUDIT_OS_NOT, "Ubuntu 14.04 / 16.04 / 18.04", "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:"14.04", pkgname:"python-lxml", pkgver:"3.3.3-1ubuntu0.2")) flag++;
if (ubuntu_check(osver:"14.04", pkgname:"python3-lxml", pkgver:"3.3.3-1ubuntu0.2")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"python-lxml", pkgver:"3.5.0-1ubuntu0.1")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"python3-lxml", pkgver:"3.5.0-1ubuntu0.1")) flag++;
if (ubuntu_check(osver:"18.04", pkgname:"python-lxml", pkgver:"4.2.1-1ubuntu0.1")) flag++;
if (ubuntu_check(osver:"18.04", pkgname:"python3-lxml", pkgver:"4.2.1-1ubuntu0.1")) flag++;

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    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, "python-lxml / python3-lxml");
}