Ubuntu 16.04 LTS / 18.04 LTS / 18.10 / 19.04 : ghostscript vulnerability (USN-3970-1)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-3970-1. 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(124717);
  script_version("1.4");
  script_cvs_date("Date: 2020/01/21");

  script_cve_id("CVE-2019-3839");
  script_xref(name:"USN", value:"3970-1");

  script_name(english:"Ubuntu 16.04 LTS / 18.04 LTS / 18.10 / 19.04 : ghostscript vulnerability (USN-3970-1)");
  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 Ghostscript incorrectly handled certain
PostScript files. If a user or automated system were tricked into
processing a specially crafted file, a remote attacker could possibly
use this issue to access arbitrary files, execute arbitrary code, or
cause a denial of service.

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/3970-1/"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected ghostscript and / or libgs9 packages."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/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:ghostscript");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libgs9");
  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:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:19.04");

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/05/16");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/05/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/05/09");
  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|18\.10|19\.04)$", string:release)) audit(AUDIT_OS_NOT, "Ubuntu 16.04 / 18.04 / 18.10 / 19.04", "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:"ghostscript", pkgver:"9.26~dfsg+0-0ubuntu0.16.04.9")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"libgs9", pkgver:"9.26~dfsg+0-0ubuntu0.16.04.9")) flag++;
if (ubuntu_check(osver:"18.04", pkgname:"ghostscript", pkgver:"9.26~dfsg+0-0ubuntu0.18.04.9")) flag++;
if (ubuntu_check(osver:"18.04", pkgname:"libgs9", pkgver:"9.26~dfsg+0-0ubuntu0.18.04.9")) flag++;
if (ubuntu_check(osver:"18.10", pkgname:"ghostscript", pkgver:"9.26~dfsg+0-0ubuntu0.18.10.9")) flag++;
if (ubuntu_check(osver:"18.10", pkgname:"libgs9", pkgver:"9.26~dfsg+0-0ubuntu0.18.10.9")) flag++;
if (ubuntu_check(osver:"19.04", pkgname:"ghostscript", pkgver:"9.26~dfsg+0-0ubuntu7.1")) flag++;
if (ubuntu_check(osver:"19.04", pkgname:"libgs9", pkgver:"9.26~dfsg+0-0ubuntu7.1")) 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, "ghostscript / libgs9");
}