Ubuntu 20.04 LTS : Linux kernel (OEM) vulnerabilities (USN-5218-1)

#%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-5218-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

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

if (description)
{
  script_id(156613);
  script_version("1.11");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/08/28");

  script_cve_id(
    "CVE-2021-3760",
    "CVE-2021-4002",
    "CVE-2021-4204",
    "CVE-2021-20321",
    "CVE-2021-41864",
    "CVE-2021-43056",
    "CVE-2021-43267",
    "CVE-2021-43389"
  );
  script_xref(name:"USN", value:"5218-1");

  script_name(english:"Ubuntu 20.04 LTS : Linux kernel (OEM) vulnerabilities (USN-5218-1)");

  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-5218-1 advisory.

    Nadav Amit discovered that the hugetlb implementation in the Linux kernel did not perform TLB flushes
    under certain conditions. A local attacker could use this to leak or alter data from other processes that
    use huge pages. (CVE-2021-4002)

    It was discovered that the eBPF implementation in the Linux kernel did not properly validate the memory
    size of certain ring buffer operation arguments. A local attacker could use this to cause a denial of
    service (system crash) or possibly execute arbitrary code. (CVE-2021-4204)

    It was discovered that a race condition existed in the overlay file system implementation in the Linux
    kernel. A local attacker could use this to cause a denial of service (system crash). (CVE-2021-20321)

    It was discovered that the NFC subsystem in the Linux kernel contained a use-after-free vulnerability in
    its NFC Controller Interface (NCI) implementation. A local attacker could possibly use this to cause a
    denial of service (system crash) or execute arbitrary code. (CVE-2021-3760)

    It was discovered that an integer overflow could be triggered in the eBPF implementation in the Linux
    kernel when preallocating objects for stack maps. A privileged local attacker could use this to cause a
    denial of service or possibly execute arbitrary code. (CVE-2021-41864)

    It was discovered that the KVM implementation for POWER8 processors in the Linux kernel did not properly
    keep track if a wakeup event could be resolved by a guest. An attacker in a guest VM could possibly use
    this to cause a denial of service (host OS crash). (CVE-2021-43056)

    It was discovered that the TIPC Protocol implementation in the Linux kernel did not properly validate
    MSG_CRYPTO messages in some situations. An attacker could use this to cause a denial of service (system
    crash) or possibly execute arbitrary code. (CVE-2021-43267)

    It was discovered that the ISDN CAPI implementation in the Linux kernel contained a race condition in
    certain situations that could trigger an array out-of-bounds bug. A privileged local attacker could
    possibly use this to cause a denial of service or execute arbitrary code. (CVE-2021-43389)

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-5218-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:H/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-43267");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/10/02");
  script_set_attribute(attribute:"patch_publication_date", value:"2022/01/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2022/01/11");

  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-5.13.0-1026-oem");
  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("linux_alt_patch_detect.nasl", "ssh_get_info.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': {
    '5.13.0': {
      'oem': '5.13.0-1026'
    }
  }
};

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-5218-1');
}

if (get_one_kb_item('Host/ksplice/kernel-cves'))
{
  var cve_list = make_list('CVE-2021-3760', 'CVE-2021-4002', 'CVE-2021-4204', 'CVE-2021-20321', 'CVE-2021-41864', 'CVE-2021-43056', 'CVE-2021-43267', 'CVE-2021-43389');
  if (ksplice_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for USN-5218-1');
  }
  else
  {
    extra = extra + ksplice_reporting_text();
  }
}
if (extra) {
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : extra
  );
  exit(0);
}