SUSE SLES11 Security Update : grub2 (SUSE-SU-2020:14461-1)

#%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
#
# The package checks in this plugin were extracted from
# SUSE update advisory SUSE-SU-2020:14461-1. The text itself
# is copyright (C) SUSE.
##

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(150591);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2022/12/06");

  script_cve_id("CVE-2020-15705");
  script_xref(name:"SuSE", value:"SUSE-SU-2020:14461-1");
  script_xref(name:"IAVA", value:"2020-A-0349");
  script_xref(name:"CEA-ID", value:"CEA-2020-0061");

  script_name(english:"SUSE SLES11 Security Update : grub2 (SUSE-SU-2020:14461-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote SUSE host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The remote SUSE Linux SLES11 host has packages installed that are affected by a vulnerability as referenced in the SUSE-
SU-2020:14461-1 advisory.

  - GRUB2 fails to validate kernel signature when booted directly without shim, allowing secure boot to be
    bypassed. This only affects systems where the kernel signing certificate has been imported directly into
    the secure boot database and the GRUB image is booted directly without the use of shim. This issue affects
    GRUB2 version 2.04 and prior versions. (CVE-2020-15705)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.suse.com/1174421");
  # https://lists.suse.com/pipermail/sle-security-updates/2020-August/007297.html
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?9d5daf50");
  script_set_attribute(attribute:"see_also", value:"https://www.suse.com/security/cve/CVE-2020-15705");
  script_set_attribute(attribute:"solution", value:
"Update the affected grub2-x86_64-efi and / or grub2-x86_64-xen packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/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:H/PR:H/UI:N/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:"cvss_score_source", value:"CVE-2020-15705");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/07/29");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/08/25");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/06/10");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:grub2-x86_64-efi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:grub2-x86_64-xen");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:suse_linux:11");
  script_set_attribute(attribute:"stig_severity", value:"II");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"SuSE Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2021-2022 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/cpu", "Host/SuSE/release", "Host/SuSE/rpm-list");

  exit(0);
}


include('audit.inc');
include('global_settings.inc');
include('misc_func.inc');
include('rpm.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/SuSE/release");
if (isnull(release) || release !~ "^(SLED|SLES)") audit(AUDIT_OS_NOT, "SUSE");
os_ver = pregmatch(pattern: "^(SLE(S|D)\d+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'SUSE');
os_ver = os_ver[1];
if (! preg(pattern:"^(SLES11)$", string:os_ver)) audit(AUDIT_OS_NOT, 'SUSE SLES11', 'SUSE ' + os_ver);

if (!get_kb_item("Host/SuSE/rpm-list")) 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$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'SUSE ' + os_ver, cpu);

sp = get_kb_item("Host/SuSE/patchlevel");
if (isnull(sp)) sp = "0";
if (os_ver == "SLES11" && (! preg(pattern:"^(4)$", string:sp))) audit(AUDIT_OS_NOT, "SLES11 SP4", os_ver + " SP" + sp);

pkgs = [
    {'reference':'grub2-x86_64-efi-2.00-0.66.21', 'sp':'4', 'cpu':'x86_64', 'release':'SLES11', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'SLES_SAP-release-11.4'},
    {'reference':'grub2-x86_64-xen-2.00-0.66.21', 'sp':'4', 'cpu':'x86_64', 'release':'SLES11', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'SLES_SAP-release-11.4'},
    {'reference':'grub2-x86_64-efi-2.00-0.66.21', 'sp':'4', 'cpu':'x86_64', 'release':'SLES11', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'sles-release-11.4'},
    {'reference':'grub2-x86_64-xen-2.00-0.66.21', 'sp':'4', 'cpu':'x86_64', 'release':'SLES11', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'sles-release-11.4'}
];

flag = 0;
foreach package_array ( pkgs ) {
  reference = NULL;
  release = NULL;
  sp = NULL;
  cpu = NULL;
  exists_check = NULL;
  rpm_spec_vers_cmp = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) release = package_array['release'];
  if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
  if (!empty_or_null(package_array['cpu'])) cpu = package_array['cpu'];
  if (!empty_or_null(package_array['exists_check'])) exists_check = package_array['exists_check'];
  if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
  if (reference && release && exists_check) {
    if (rpm_exists(release:release, rpm:exists_check) && rpm_check(release:release, sp:sp, cpu:cpu, reference:reference, rpm_spec_vers_cmp:rpm_spec_vers_cmp)) flag++;
  }
  else if (reference && release) {
    if (rpm_check(release:release, sp:sp, cpu:cpu, reference:reference, rpm_spec_vers_cmp:rpm_spec_vers_cmp)) flag++;
  }
}

if (flag)
{
  ltss_plugin_caveat = '\n' +
    'NOTE: This vulnerability check contains fixes that apply to\n' +
    'packages only available in SUSE Enterprise Linux Server LTSS\n' +
    'repositories. Access to these package security updates require\n' +
    'a paid SUSE LTSS subscription.\n';
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : rpm_report_get() + ltss_plugin_caveat
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'grub2-x86_64-efi / grub2-x86_64-xen');
}