Ubuntu 16.04 LTS / 18.04 LTS : systemd vulnerabilities (USN-4269-1)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-4269-1. 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(133523);
  script_version("1.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/10/20");

  script_cve_id(
    "CVE-2018-16888",
    "CVE-2019-20386",
    "CVE-2019-3843",
    "CVE-2019-3844",
    "CVE-2020-1712"
  );
  script_xref(name:"USN", value:"4269-1");

  script_name(english:"Ubuntu 16.04 LTS / 18.04 LTS : systemd vulnerabilities (USN-4269-1)");

  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 systemd incorrectly handled certain PIDFile
files. A local attacker could possibly use this issue to trick systemd
into killing privileged processes. This issue only affected Ubuntu
16.04 LTS. (CVE-2018-16888)

It was discovered that systemd incorrectly handled certain udevadm
trigger commands. A local attacker could possibly use this issue to
cause systemd to consume resources, leading to a denial of service.
(CVE-2019-20386)

Jann Horn discovered that systemd incorrectly handled services that
use the DynamicUser property. A local attacker could possibly use this
issue to access resources owned by a different service in the future.
This issue only affected Ubuntu 18.04 LTS. (CVE-2019-3843,
CVE-2019-3844)

Tavis Ormandy discovered that systemd incorrectly handled certain
Polkit queries. A local attacker could use this issue to cause systemd
to crash, resulting in a denial of service, or possibly execute
arbitrary code and escalate privileges. (CVE-2020-1712).

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-4269-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/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-2020-1712");

  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:"2019/01/14");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/02/05");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/02/06");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:systemd");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:systemd-container");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:systemd-coredump");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:systemd-journal-remote");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:systemd-sysv");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:systemd-tests");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:udev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:udev-udeb");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libnss-myhostname");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libnss-mymachines");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libnss-resolve");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libnss-systemd");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libpam-systemd");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libsystemd-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libsystemd0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libudev-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libudev1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libudev1-udeb");
  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) 2020-2023 Canonical, Inc. / NASL script (C) 2020-2023 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 (! ('16.04' >< os_release || '18.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 16.04 / 18.04', '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': '16.04', 'pkgname': 'libnss-myhostname', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '16.04', 'pkgname': 'libnss-mymachines', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '16.04', 'pkgname': 'libnss-resolve', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '16.04', 'pkgname': 'libpam-systemd', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '16.04', 'pkgname': 'libsystemd-dev', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '16.04', 'pkgname': 'libsystemd0', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '16.04', 'pkgname': 'libudev-dev', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '16.04', 'pkgname': 'libudev1', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '16.04', 'pkgname': 'libudev1-udeb', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '16.04', 'pkgname': 'systemd', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '16.04', 'pkgname': 'systemd-container', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '16.04', 'pkgname': 'systemd-coredump', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '16.04', 'pkgname': 'systemd-journal-remote', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '16.04', 'pkgname': 'systemd-sysv', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '16.04', 'pkgname': 'udev', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '16.04', 'pkgname': 'udev-udeb', 'pkgver': '229-4ubuntu21.27'},
    {'osver': '18.04', 'pkgname': 'libnss-myhostname', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'libnss-mymachines', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'libnss-resolve', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'libnss-systemd', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'libpam-systemd', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'libsystemd-dev', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'libsystemd0', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'libudev-dev', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'libudev1', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'libudev1-udeb', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'systemd', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'systemd-container', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'systemd-coredump', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'systemd-journal-remote', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'systemd-sysv', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'systemd-tests', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'udev', 'pkgver': '237-3ubuntu10.38'},
    {'osver': '18.04', 'pkgname': 'udev-udeb', 'pkgver': '237-3ubuntu10.38'}
];

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_WARNING,
    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, 'libnss-myhostname / libnss-mymachines / libnss-resolve / etc');
}