Amazon Linux 2023 : grub2-common, grub2-efi-aa64, grub2-efi-aa64-cdboot (ALAS2023-2023-020)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2023 Security Advisory ALAS2023-2023-020.
##

include('compat.inc');

if (description)
{
  script_id(173192);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/01/17");

  script_cve_id(
    "CVE-2021-3695",
    "CVE-2021-3696",
    "CVE-2021-3697",
    "CVE-2021-3981",
    "CVE-2022-2601",
    "CVE-2022-3775",
    "CVE-2022-28733",
    "CVE-2022-28734",
    "CVE-2022-28735",
    "CVE-2022-28736"
  );
  script_xref(name:"IAVA", value:"2020-A-0349");

  script_name(english:"Amazon Linux 2023 : grub2-common, grub2-efi-aa64, grub2-efi-aa64-cdboot (ALAS2023-2023-020)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux 2023 host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2023-020 advisory.

  - A crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may
    take advantage of that to cause heap data corruption or eventually arbitrary code execution and circumvent
    secure boot protections. This issue has a high complexity to be exploited as an attacker needs to perform
    some triage over the heap layout to achieve signifcant results, also the values written into the memory
    are repeated three times in a row making difficult to produce valid payloads. This flaw affects grub2
    versions prior grub-2.12. (CVE-2021-3695)

  - A heap out-of-bounds write may heppen during the handling of Huffman tables in the PNG reader. This may
    lead to data corruption in the heap space. Confidentiality, Integrity and Availablity impact may be
    considered Low as it's very complex to an attacker control the encoding and positioning of corrupted
    Huffman entries to achieve results such as arbitrary code execution and/or secure boot circumvention. This
    flaw affects grub2 versions prior grub-2.12. (CVE-2021-3696)

  - A crafted JPEG image may lead the JPEG reader to underflow its data pointer, allowing user-controlled data
    to be written in heap. To a successful to be performed the attacker needs to perform some triage over the
    heap layout and craft an image with a malicious format and payload. This vulnerability can lead to data
    corruption and eventual code execution or secure boot circumvention. This flaw affects grub2 versions
    prior grub-2.12. (CVE-2021-3697)

  - 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)

  - A buffer overflow was found in grub_font_construct_glyph(). A malicious crafted pf2 font can lead to an
    overflow when calculating the max_glyph_size value, allocating a smaller than needed buffer for the glyph,
    this further leads to a buffer overflow and a heap based out-of-bounds write. An attacker may use this
    vulnerability to circumvent the secure boot mechanism. (CVE-2022-2601)

  - When rendering certain unicode sequences, grub2's font code doesn't proper validate if the informed
    glyph's width and height is constrained within bitmap size. As consequence an attacker can craft an input
    which will lead to a out-of-bounds write into grub2's heap, leading to memory corruption and availability
    issues. Although complex, arbitrary code execution could not be discarded. (CVE-2022-3775)

  - grub2: Integer underflow in grub_net_recv_ip4_packets (CVE-2022-28733)

  - grub2: Out-of-bound write when handling split HTTP headers (CVE-2022-28734)

  - grub2: shim_lock verifier allows non-kernel files to be loaded (CVE-2022-28735)

  - grub2: use-after-free in grub_cmd_chainloader() (CVE-2022-28736)

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://alas.aws.amazon.com/AL2023/ALAS-2023-020.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2021-3695.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2021-3696.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2021-3697.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2021-3981.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2022-2601.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2022-28733.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2022-28734.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2022-28735.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2022-28736.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2022-3775.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/faqs.html");
  script_set_attribute(attribute:"solution", value:
"Run 'dnf update grub2 --releasever=2023.0.20230222 ' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:M/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:N/UI:R/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-2021-3696");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2022-2601");

  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:"2020/07/30");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/02/17");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/03/21");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-common");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-debugsource");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-efi-aa64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-efi-aa64-cdboot");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-efi-aa64-ec2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-efi-aa64-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-efi-x64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-efi-x64-cdboot");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-efi-x64-ec2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-efi-x64-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-emu");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-emu-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-emu-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-pc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-pc-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-tools");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-tools-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-tools-efi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-tools-efi-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-tools-extra");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-tools-extra-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-tools-minimal");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:grub2-tools-minimal-debuginfo");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2023");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"II");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2023-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");

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

  exit(0);
}

include("rpm.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

var alas_release = get_kb_item("Host/AmazonLinux/release");
if (isnull(alas_release) || !strlen(alas_release)) audit(AUDIT_OS_NOT, "Amazon Linux");
var os_ver = pregmatch(pattern: "^AL(A|\d+|-\d+)", string:alas_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
os_ver = os_ver[1];
if (os_ver != "-2023")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux 2023", "Amazon Linux " + os_ver);
}

if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

var pkgs = [
    {'reference':'grub2-common-2.06-61.amzn2023.0.3', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-debuginfo-2.06-61.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-debuginfo-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-debugsource-2.06-61.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-debugsource-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-efi-aa64-2.06-61.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-efi-aa64-cdboot-2.06-61.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-efi-aa64-ec2-2.06-61.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-efi-aa64-modules-2.06-61.amzn2023.0.3', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-efi-x64-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-efi-x64-cdboot-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-efi-x64-ec2-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-efi-x64-modules-2.06-61.amzn2023.0.3', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-emu-2.06-61.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-emu-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-emu-debuginfo-2.06-61.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-emu-debuginfo-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-emu-modules-2.06-61.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-emu-modules-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-pc-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-pc-modules-2.06-61.amzn2023.0.3', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-tools-2.06-61.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-tools-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-tools-debuginfo-2.06-61.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-tools-debuginfo-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-tools-efi-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-tools-efi-debuginfo-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-tools-extra-2.06-61.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-tools-extra-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-tools-extra-debuginfo-2.06-61.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-tools-extra-debuginfo-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-tools-minimal-2.06-61.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-tools-minimal-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-tools-minimal-debuginfo-2.06-61.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'grub2-tools-minimal-debuginfo-2.06-61.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE}
];

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 = 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 && (!exists_check || rpm_exists(release:_release, rpm:exists_check))) {
    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_WARNING,
      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-debuginfo / grub2-debugsource / etc");
}