Ubuntu 20.04 LTS : Linux kernel vulnerabilities (USN-5113-1)

#%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-5113-1. 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(154241);
  script_version("1.8");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/01/09");

  script_cve_id(
    "CVE-2020-3702",
    "CVE-2021-3732",
    "CVE-2021-3739",
    "CVE-2021-3743",
    "CVE-2021-3753",
    "CVE-2021-38166",
    "CVE-2021-40490",
    "CVE-2021-42008"
  );
  script_xref(name:"USN", value:"5113-1");

  script_name(english:"Ubuntu 20.04 LTS : Linux kernel vulnerabilities (USN-5113-1)");

  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-5113-1 advisory.

  - u'Specifically timed and handcrafted traffic can cause internal errors in a WLAN device that lead to
    improper layer 2 Wi-Fi encryption with a consequent possibility of information disclosure over the air for
    a discrete set of traffic' in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon
    Consumer IOT, Snapdragon Industrial IOT, Snapdragon Mobile, Snapdragon Voice & Music, Snapdragon
    Wearables, Snapdragon Wired Infrastructure and Networking in APQ8053, IPQ4019, IPQ8064, MSM8909W,
    MSM8996AU, QCA9531, QCN5502, QCS405, SDX20, SM6150, SM7150 (CVE-2020-3702)

  - A flaw was found in the Linux kernel's OverlayFS subsystem in the way the user mounts the TmpFS filesystem
    with OverlayFS. This flaw allows a local user to gain access to hidden files that should not be
    accessible. (CVE-2021-3732)

  - A NULL pointer dereference flaw was found in the btrfs_rm_device function in fs/btrfs/volumes.c in the
    Linux Kernel, where triggering the bug requires CAP_SYS_ADMIN'. This flaw allows a local attacker to
    crash the system or leak kernel internal information. The highest threat from this vulnerability is to
    system availability. (CVE-2021-3739)

  - An out-of-bounds (OOB) memory read flaw was found in the Qualcomm IPC router protocol in the Linux kernel.
    A missing sanity check allows a local attacker to gain access to out-of-bounds memory, leading to a system
    crash or a leak of internal kernel information. The highest threat from this vulnerability is to system
    availability. (CVE-2021-3743)

  - A race problem was seen in the vt_k_ioctl in drivers/tty/vt/vt_ioctl.c in the Linux kernel, which may
    cause an out of bounds read in vt as the write access to vc_mode is not protected by lock-in vt_ioctl
    (KDSETMDE). The highest threat from this vulnerability is to data confidentiality. (CVE-2021-3753)

  - In kernel/bpf/hashtab.c in the Linux kernel through 5.13.8, there is an integer overflow and out-of-bounds
    write when many elements are placed in a single bucket. NOTE: exploitation might be impractical without
    the CAP_SYS_ADMIN capability. (CVE-2021-38166)

  - A race condition was discovered in ext4_write_inline_data_end in fs/ext4/inline.c in the ext4 subsystem in
    the Linux kernel through 5.13.13. (CVE-2021-40490)

  - The decode_data function in drivers/net/hamradio/6pack.c in the Linux kernel before 5.13.13 has a slab
    out-of-bounds write. Input from a process that has the CAP_NET_ADMIN capability can lead to root access.
    (CVE-2021-42008)

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-5113-1");
  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: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-2021-42008");

  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:"2020/09/08");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/10/19");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/10/20");

  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-5.11.0-1020-aws");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-1021-gcp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-38-generic");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-38-generic-64k");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-38-generic-lpae");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-38-lowlatency");
  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) 2021-2024 Canonical, Inc. / NASL script (C) 2021-2024 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': {
    '5.11.0': {
      'generic': '5.11.0-38',
      'generic-64k': '5.11.0-38',
      'generic-lpae': '5.11.0-38',
      'lowlatency': '5.11.0-38',
      'aws': '5.11.0-1020',
      'gcp': '5.11.0-1021'
    }
  }
};

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 = 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-5113-1');
}

if (get_one_kb_item('Host/ksplice/kernel-cves'))
{
  var cve_list = make_list('CVE-2020-3702', 'CVE-2021-3732', 'CVE-2021-3739', 'CVE-2021-3743', 'CVE-2021-3753', 'CVE-2021-38166', 'CVE-2021-40490', 'CVE-2021-42008');
  if (ksplice_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for USN-5113-1');
  }
  else
  {
    extra = extra + ksplice_reporting_text();
  }
}
if (extra) {
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : extra
  );
  exit(0);
}