Oracle Linux 8 : grub2 (ELSA-2022-2110)

##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Oracle Linux Security Advisory ELSA-2022-2110.
##

include('compat.inc');

if (description)
{
  script_id(161311);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2022/05/18");

  script_cve_id("CVE-2021-3981");

  script_name(english:"Oracle Linux 8 : grub2 (ELSA-2022-2110)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Oracle Linux host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The remote Oracle Linux 8 host has packages installed that are affected by a vulnerability as referenced in the
ELSA-2022-2110 advisory.

  - A flaw in grub2 was found where its configuration file, known as grub.cfg, is being created with the wrong
    permission set allowing non privileged users to read its content. This represents a low severity
    confidentiality issue, as those users can eventually read any encrypted passwords present in grub.cfg.
    This flaw affects grub2 2.06 and previous versions. This issue has been fixed in grub upstream but no
    version with the fix is currently released. (CVE-2021-3981)

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://linux.oracle.com/errata/ELSA-2022-2110.html");
  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:N/A:N");
  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:L/UI:N/S:U/C:L/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-3981");

  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:"2022/03/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2022/05/17");
  script_set_attribute(attribute:"plugin_publication_date", value:"2022/05/18");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:8");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-common");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-efi-aa64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-efi-aa64-cdboot");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-efi-aa64-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-efi-ia32");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-efi-ia32-cdboot");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-efi-ia32-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-efi-x64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-efi-x64-cdboot");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-efi-x64-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-pc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-pc-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-tools");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-tools-efi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-tools-extra");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:grub2-tools-minimal");
  script_end_attributes();

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

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

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

  exit(0);
}


include('rpm.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item('Host/OracleLinux')) audit(AUDIT_OS_NOT, 'Oracle Linux');
var release = get_kb_item("Host/RedHat/release");
if (isnull(release) || !pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux)", string:release)) audit(AUDIT_OS_NOT, 'Oracle Linux');
var os_ver = pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux) .*release ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Oracle Linux');
var os_ver = os_ver[1];
if (! preg(pattern:"^8([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Oracle Linux 8', 'Oracle Linux ' + os_ver);

if (!get_kb_item('Host/RedHat/rpm-list')) 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$" && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Oracle Linux', cpu);

var pkgs = [
    {'reference':'grub2-common-2.02-123.0.1.el8', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-efi-aa64-2.02-123.0.1.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-efi-aa64-cdboot-2.02-123.0.1.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-efi-aa64-modules-2.02-123.0.1.el8', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-efi-ia32-2.02-123.0.1.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-efi-ia32-cdboot-2.02-123.0.1.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-efi-ia32-modules-2.02-123.0.1.el8', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-efi-x64-2.02-123.0.1.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-efi-x64-cdboot-2.02-123.0.1.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-efi-x64-modules-2.02-123.0.1.el8', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-pc-2.02-123.0.1.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-pc-modules-2.02-123.0.1.el8', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-tools-2.02-123.0.1.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-tools-2.02-123.0.1.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-tools-efi-2.02-123.0.1.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-tools-extra-2.02-123.0.1.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-tools-extra-2.02-123.0.1.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-tools-minimal-2.02-123.0.1.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
    {'reference':'grub2-tools-minimal-2.02-123.0.1.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'}
];

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

if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_NOTE,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'grub2-common / grub2-efi-aa64 / grub2-efi-aa64-cdboot / etc');
}