Ubuntu 20.04 LTS : Linux kernel (Azure CVM) vulnerabilities (USN-5706-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-5706-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

include('compat.inc');

if (description)
{
  script_id(166668);
  script_version("1.6");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/08/27");

  script_cve_id(
    "CVE-2021-4159",
    "CVE-2022-2318",
    "CVE-2022-3176",
    "CVE-2022-20369",
    "CVE-2022-26365",
    "CVE-2022-26373",
    "CVE-2022-33740",
    "CVE-2022-33741",
    "CVE-2022-33742",
    "CVE-2022-33744",
    "CVE-2022-36879"
  );
  script_xref(name:"USN", value:"5706-1");

  script_name(english:"Ubuntu 20.04 LTS : Linux kernel (Azure CVM) vulnerabilities (USN-5706-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 20.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in
the USN-5706-1 advisory.

    It was discovered that the BPF verifier in the Linux kernel did not properly handle internal data
    structures. A local attacker could use this to expose sensitive information (kernel memory).
    (CVE-2021-4159)

    It was discovered that an out-of-bounds write vulnerability existed in the Video for Linux 2 (V4L2)
    implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system
    crash) or possibly execute arbitrary code. (CVE-2022-20369)

    Duoming Zhou discovered that race conditions existed in the timer handling implementation of the Linux
    kernel's Rose X.25 protocol layer, resulting in use-after-free vulnerabilities. A local attacker could use
    this to cause a denial of service (system crash). (CVE-2022-2318)

    Roger Pau Monn discovered that the Xen virtual block driver in the Linux kernel did not properly
    initialize memory pages to be used for shared communication with the backend. A local attacker could use
    this to expose sensitive information (guest kernel memory). (CVE-2022-26365)

    Pawan Kumar Gupta, Alyssa Milburn, Amit Peled, Shani Rehana, Nir Shildan and Ariel Sabba discovered that
    some Intel processors with Enhanced Indirect Branch Restricted Speculation (eIBRS) did not properly handle
    RET instructions after a VM exits. A local attacker could potentially use this to expose sensitive
    information. (CVE-2022-26373)

    Eric Biggers discovered that a use-after-free vulnerability existed in the io_uring subsystem in the Linux
    kernel. A local attacker could possibly use this to cause a denial of service (system crash) or possibly
    execute arbitrary code. (CVE-2022-3176)

    Roger Pau Monn discovered that the Xen paravirtualization frontend in the Linux kernel did not properly
    initialize memory pages to be used for shared communication with the backend. A local attacker could use
    this to expose sensitive information (guest kernel memory). (CVE-2022-33740)

    It was discovered that the Xen paravirtualization frontend in the Linux kernel incorrectly shared
    unrelated data when communicating with certain backends. A local attacker could use this to cause a denial
    of service (guest crash) or expose sensitive information (guest kernel memory). (CVE-2022-33741,
    CVE-2022-33742)

    Oleksandr Tyshchenko discovered that the Xen paravirtualization platform in the Linux kernel on ARM
    platforms contained a race condition in certain situations. An attacker in a guest VM could use this to
    cause a denial of service in the host OS. (CVE-2022-33744)

    It was discovered that the Netlink Transformation (XFRM) subsystem in the Linux kernel contained a
    reference counting error. A local attacker could use this to cause a denial of service (system crash).
    (CVE-2022-36879)

Tenable has extracted the preceding description block directly from the Ubuntu 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://ubuntu.com/security/notices/USN-5706-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:P/I:N/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:L/PR:L/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-2022-33742");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2022-3176");

  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:"2022/05/06");
  script_set_attribute(attribute:"patch_publication_date", value:"2022/10/27");
  script_set_attribute(attribute:"plugin_publication_date", value:"2022/10/28");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.4.0-1092-azure-fde");
  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) 2022-2024 Canonical, Inc. / NASL script (C) 2022-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl", "linux_alt_patch_detect.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}

include('debian_package.inc');
include('ksplice.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 (! ('20.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 20.04', '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 kernel_mappings = {
  '20.04': {
    '5.4.0': {
      'azure-fde': '5.4.0-1092'
    }
  }
};

var host_kernel_release = get_kb_item('Host/uptrack-uname-r');
if (empty_or_null(host_kernel_release)) host_kernel_release = get_kb_item_or_exit('Host/uname-r');
var host_kernel_base_version = get_kb_item_or_exit('Host/Debian/kernel-base-version');
var host_kernel_type = get_kb_item_or_exit('Host/Debian/kernel-type');
if(empty_or_null(kernel_mappings[os_release][host_kernel_base_version][host_kernel_type])) audit(AUDIT_INST_VER_NOT_VULN, 'kernel ' + host_kernel_release);

var extra = '';
var kernel_fixed_version = kernel_mappings[os_release][host_kernel_base_version][host_kernel_type] + "-" + host_kernel_type;
if (deb_ver_cmp(ver1:host_kernel_release, ver2:kernel_fixed_version) < 0)
{
  extra += 'Running Kernel level of ' + host_kernel_release + ' does not meet the minimum fixed level of ' + kernel_fixed_version + ' for this advisory.\n\n';
}
  else
{
  audit(AUDIT_PATCH_INSTALLED, 'Kernel package for USN-5706-1');
}

if (get_one_kb_item('Host/ksplice/kernel-cves'))
{
  var cve_list = make_list('CVE-2021-4159', 'CVE-2022-2318', 'CVE-2022-3176', 'CVE-2022-20369', 'CVE-2022-26365', 'CVE-2022-26373', 'CVE-2022-33740', 'CVE-2022-33741', 'CVE-2022-33742', 'CVE-2022-33744', 'CVE-2022-36879');
  if (ksplice_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for USN-5706-1');
  }
  else
  {
    extra = extra + ksplice_reporting_text();
  }
}
if (extra) {
  security_report_v4(
    port       : 0,
    severity   : SECURITY_NOTE,
    extra      : extra
  );
  exit(0);
}