Vulnerabilities > CVE-2018-17205 - Reachable Assertion vulnerability in multiple products

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-3873-1. 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(121506);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/02/20");

  script_cve_id("CVE-2018-17204", "CVE-2018-17205", "CVE-2018-17206");
  script_xref(name:"USN", value:"3873-1");

  script_name(english:"Ubuntu 16.04 LTS / 18.04 LTS : openvswitch vulnerabilities (USN-3873-1)");
  script_summary(english:"Checks dpkg output for updated package.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Ubuntu host is missing a security-related patch."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"It was discovered that Open vSwitch incorrectly decoded certain
packets. A remote attacker could possibly use this issue to cause Open
vSwitch to crash, resulting in a denial of service. (CVE-2018-17204)

It was discovered that Open vSwitch incorrectly handled processing
certain flows. A remote attacker could possibly use this issue to
cause Open vSwitch to crash, resulting in a denial of service. This
issue only affected Ubuntu 18.04 LTS. (CVE-2018-17205)

It was discovered that Open vSwitch incorrectly handled BUNDLE action
decoding. A remote attacker could possibly use this issue to cause
Open vSwitch to crash, resulting in a denial of service.
(CVE-2018-17206).

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/3873-1/"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected openvswitch-common package."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
  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:N/S:U/C:N/I:N/A:H");
  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:openvswitch-common");
  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:"2018/09/19");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/01/30");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/01/31");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"Ubuntu Security Notice (C) 2019-2020 Canonical, Inc. / NASL script (C) 2019-2020 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:"^(16\.04|18\.04)$", string:release)) audit(AUDIT_OS_NOT, "Ubuntu 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:"16.04", pkgname:"openvswitch-common", pkgver:"2.5.5-0ubuntu0.16.04.2")) flag++;
if (ubuntu_check(osver:"18.04", pkgname:"openvswitch-common", pkgver:"2.9.2-0ubuntu0.18.04.3")) 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, "openvswitch-common");
}