Rocky Linux 8 [CIQ] Security Update: shim-unsigned-aarch64 Multiple Vulnerabilities (crlsa-2021_1734)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(358110);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/01");

  script_cve_id(
    "CVE-2020-14372",
    "CVE-2020-25632",
    "CVE-2020-25647",
    "CVE-2020-27749",
    "CVE-2020-27779",
    "CVE-2021-20225",
    "CVE-2021-20233"
  );

  script_name(english:"Rocky Linux 8 [CIQ] Security Update: shim-unsigned-aarch64 Multiple Vulnerabilities (crlsa-2021_1734)");

  script_set_attribute(attribute:"synopsis", value:
"The Rocky Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The Rocky Linux 8 host has a package installed that is affected by multiple vulnerabilities as referenced in the CIQ
crlsa-2021_1734 advisory.

    * grub2: acpi command allows privileged user to load crafted ACPI tables when Secure Boot is enabled
    (CVE-2020-14372)

    * grub2: Use-after-free in rmmod command (CVE-2020-25632)

    * grub2: Out-of-bounds write in grub_usb_device_initialize() (CVE-2020-25647)

    * grub2: Stack buffer overflow in grub_parser_split_cmdline() (CVE-2020-27749)

    * grub2: cutmem command allows privileged user to remove memory regions when Secure Boot is enabled
    (CVE-2020-27779)

    * grub2: Heap out-of-bounds write in short form option parser (CVE-2021-20225)

    * grub2: Heap out-of-bounds write due to miscalculation of space required for quoting (CVE-2021-20233)

Tenable has extracted the preceding description block directly from the CIQ security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1886936");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1899966");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1879577");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1900698");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1924696");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1873150");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1926263");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1873150");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1879577");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1886936");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1899966");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1900698");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1924696");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1926263");
  script_set_attribute(attribute:"see_also", value:"https://errata.build.resf.org/RLSA-2021:1734");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2021:1734");
  # https://security.access.redhat.com/data/csaf/v2/advisories/2025/rhsa-2021_1734.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?ff68860e");
  # https://github.com/ctrliq/advisories/blob/main/csaf/advisories/rocky/2021/crlsa-2021_1734.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?75ceba5e");
  script_set_attribute(attribute:"solution", value:
"Update the affected shim-unsigned-aarch64 package based on the guidance in CIQ advisory crlsa-2021_1734.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  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:H/UI:N/S:C/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-2021-20233");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"vendor_severity", value:"Unknown");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/07/30");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/05/18");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/01");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.nasl");
  script_require_keys("Host/OS/extended-third-party", "Host/local_checks_enabled", "Host/RockyLinux/release", "Host/RockyLinux/rpm-list", "Host/cpu");

  exit(0);
}
include('rpm2.inc');

var third_party_support = get_kb_item('Host/OS/extended-third-party');
if (empty_or_null(third_party_support) || third_party_support != 'CIQ') exit(0, 'CIQ support not enabled.');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_product = get_kb_item('installed_os/local/SSH/0/product');
if (isnull(os_product) || 'Rocky Linux' >!< os_product) audit(AUDIT_OS_NOT, 'Rocky Linux');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'Rocky Linux');
if (! preg(pattern:"^8([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'Rocky Linux 8', 'Rocky Linux ' + os_version);

if (!get_kb_item('Host/RockyLinux/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Rocky Linux', cpu);


var constraints = [
  {
    'release': '8',
    'pkgs': [
      {'reference':'shim-unsigned-aarch64-15-7.el8.1.1', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'}
    ]
  }
];

var os_release = get_one_kb_item('installed_os/local/SSH/0/release');
var os_sp = get_one_kb_item('Host/*/minor_release');

var flag = 0;
var reference;
var sp;
var _cpu;
var el_string;
var rpm_spec_vers_cmp;
var epoch;
var allowmaj;
var exists_check;
var cves;
foreach var constraint ( constraints ) {
  # Check that the target release is equal to the affected release
  if (!empty_or_null(constraint['release'])){
    if (constraint['release'] != os_release) continue;
  }
  if (!empty_or_null(constraint['sp'])){
    if (constraint['sp'] != os_sp) continue;
  }
  foreach var pkg ( constraint['pkgs'] ) {
    reference = NULL;
    sp = NULL;
    _cpu = NULL;
    el_string = NULL;
    rpm_spec_vers_cmp = NULL;
    epoch = NULL;
    allowmaj = NULL;
    exists_check = NULL;
    cves = NULL;
    if (!empty_or_null(pkg['reference'])) reference = pkg['reference'];
    if (!empty_or_null(pkg['sp'])) sp = pkg['sp'];
    if (!empty_or_null(pkg['cpu'])) _cpu = pkg['cpu'];
    if (!empty_or_null(pkg['el_string'])) el_string = pkg['el_string'];
    if (!empty_or_null(pkg['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = pkg['rpm_spec_vers_cmp'];
    if (!empty_or_null(pkg['epoch'])) epoch = pkg['epoch'];
    if (!empty_or_null(pkg['allowmaj'])) allowmaj = pkg['allowmaj'];
    if (!empty_or_null(pkg['exists_check'])) exists_check = pkg['exists_check'];
    if (!empty_or_null(pkg['cves'])) cves = pkg['cves'];
    if (reference &&
        ## (no known rpm to check OR known rpm_exists)
        (!exists_check || rpm_exists(rpm:exists_check)) &&
        rpm_check(sp:sp, cpu:_cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj, cves:cves)) flag++;
  }
}


if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      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, 'shim-unsigned-aarch64');
}