Ubuntu 18.04 LTS : Linux kernel vulnerabilities (USN-4342-1)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-4342-1. The text 
# itself is copyright (C) Canonical, Inc. See 
# <http://www.ubuntu.com/usn/>. Ubuntu(R) is a registered 
# trademark of Canonical, Inc.
#

include('compat.inc');

if (description)
{
  script_id(136085);
  script_version("1.10");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/08/27");

  script_cve_id(
    "CVE-2019-16234",
    "CVE-2019-19768",
    "CVE-2020-10942",
    "CVE-2020-11884",
    "CVE-2020-8648",
    "CVE-2020-8992",
    "CVE-2020-9383"
  );
  script_xref(name:"USN", value:"4342-1");

  script_name(english:"Ubuntu 18.04 LTS : Linux kernel vulnerabilities (USN-4342-1)");

  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 18.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in
the USN-4342-1 advisory.

    Al Viro discovered that the Linux kernel for s390x systems did not properly perform page table upgrades
    for kernel sections that use secondary address mode. A local attacker could use this to cause a denial of
    service (system crash) or execute arbitrary code. (CVE-2020-11884)

    It was discovered that the Intel Wi-Fi driver in the Linux kernel did not properly check for errors in
    some situations. A local attacker could possibly use this to cause a denial of service (system crash).
    (CVE-2019-16234)

    Tristan Madani discovered that the block I/O tracing implementation in the Linux kernel contained a race
    condition. A local attacker could use this to cause a denial of service (system crash) or possibly expose
    sensitive information. (CVE-2019-19768)

    It was discovered that the vhost net driver in the Linux kernel contained a stack buffer overflow. A local
    attacker with the ability to perform ioctl() calls on /dev/vhost-net could use this to cause a denial of
    service (system crash). (CVE-2020-10942)

    It was discovered that the virtual terminal implementation in the Linux kernel contained a race condition.
    A local attacker could possibly use this to cause a denial of service (system crash) or expose sensitive
    information. (CVE-2020-8648)

    Shijie Luo discovered that the ext4 file system implementation in the Linux kernel did not properly check
    for a too-large journal size. An attacker could use this to construct a malicious ext4 image that, when
    mounted, could cause a denial of service (soft lockup). (CVE-2020-8992)

    Jordy Zomer discovered that the floppy driver in the Linux kernel did not properly check for errors in
    some situations. A local attacker could possibly use this to cause a denial of service (system crash) or
    possibly expose sensitive information. (CVE-2020-9383)

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-4342-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  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:L/UI:N/S:U/C:H/I:N/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-2020-11884");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2020-9383");

  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:"2019/09/11");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/04/30");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/04/29");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-1016-oracle");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-1018-gcp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-1018-gke");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-1020-azure");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-1023-raspi2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-51-generic");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-51-generic-lpae");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-51-lowlatency");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  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) 2020-2024 Canonical, Inc. / NASL script (C) 2020-2024 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 (! ('18.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 18.04', '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 = {
  '18.04': {
    '5.3.0': {
      'generic': '5.3.0-51',
      'generic-lpae': '5.3.0-51',
      'lowlatency': '5.3.0-51',
      'oracle': '5.3.0-1016',
      'gcp': '5.3.0-1018',
      'gke': '5.3.0-1018',
      'azure': '5.3.0-1020',
      'raspi2': '5.3.0-1023'
    }
  }
};

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-4342-1');
}

if (get_one_kb_item('Host/ksplice/kernel-cves'))
{
  var cve_list = make_list('CVE-2019-16234', 'CVE-2019-19768', 'CVE-2020-8648', 'CVE-2020-8992', 'CVE-2020-9383', 'CVE-2020-10942', 'CVE-2020-11884');
  if (ksplice_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for USN-4342-1');
  }
  else
  {
    extra = extra + ksplice_reporting_text();
  }
}
if (extra) {
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : extra
  );
  exit(0);
}