Ubuntu 16.04 ESM / 18.04 LTS : Linux kernel vulnerabilities (USN-5018-1)

#%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-5018-1. 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(151920);
  script_version("1.9");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/01/09");

  script_cve_id(
    "CVE-2020-24586",
    "CVE-2020-24587",
    "CVE-2020-26139",
    "CVE-2020-26147",
    "CVE-2020-26558",
    "CVE-2021-0129",
    "CVE-2021-23134",
    "CVE-2021-31829",
    "CVE-2021-32399",
    "CVE-2021-33034",
    "CVE-2021-33200",
    "CVE-2021-33909"
  );
  script_xref(name:"USN", value:"5018-1");
  script_xref(name:"IAVA", value:"2021-A-0350");

  script_name(english:"Ubuntu 16.04 ESM / 18.04 LTS : Linux kernel vulnerabilities (USN-5018-1)");

  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 16.04 ESM / 18.04 LTS host has a package installed that is affected by multiple vulnerabilities as
referenced in the USN-5018-1 advisory.

  - The 802.11 standard that underpins Wi-Fi Protected Access (WPA, WPA2, and WPA3) and Wired Equivalent
    Privacy (WEP) doesn't require that received fragments be cleared from memory after (re)connecting to a
    network. Under the right circumstances, when another device sends fragmented frames encrypted using WEP,
    CCMP, or GCMP, this can be abused to inject arbitrary network packets and/or exfiltrate user data.
    (CVE-2020-24586)

  - The 802.11 standard that underpins Wi-Fi Protected Access (WPA, WPA2, and WPA3) and Wired Equivalent
    Privacy (WEP) doesn't require that all fragments of a frame are encrypted under the same key. An adversary
    can abuse this to decrypt selected fragments when another device sends fragmented frames and the WEP,
    CCMP, or GCMP encryption key is periodically renewed. (CVE-2020-24587)

  - An issue was discovered in the kernel in NetBSD 7.1. An Access Point (AP) forwards EAPOL frames to other
    clients even though the sender has not yet successfully authenticated to the AP. This might be abused in
    projected Wi-Fi networks to launch denial-of-service attacks against connected clients and makes it easier
    to exploit other vulnerabilities in connected clients. (CVE-2020-26139)

  - An issue was discovered in the Linux kernel 5.8.9. The WEP, WPA, WPA2, and WPA3 implementations reassemble
    fragments even though some of them were sent in plaintext. This vulnerability can be abused to inject
    packets and/or exfiltrate selected fragments when another device sends fragmented frames and the WEP,
    CCMP, or GCMP data-confidentiality protocol is used. (CVE-2020-26147)

  - Bluetooth LE and BR/EDR secure pairing in Bluetooth Core Specification 2.1 through 5.2 may permit a nearby
    man-in-the-middle attacker to identify the Passkey used during pairing (in the Passkey authentication
    procedure) by reflection of the public key and the authentication evidence of the initiating device,
    potentially permitting this attacker to complete authenticated pairing with the responding device using
    the correct Passkey for the pairing session. The attack methodology determines the Passkey value one bit
    at a time. (CVE-2020-26558)

  - Improper access control in BlueZ may allow an authenticated user to potentially enable information
    disclosure via adjacent access. (CVE-2021-0129)

  - Use After Free vulnerability in nfc sockets in the Linux Kernel before 5.12.4 allows local attackers to
    elevate their privileges. In typical configurations, the issue can only be triggered by a privileged local
    user with the CAP_NET_RAW capability. (CVE-2021-23134)

  - kernel/bpf/verifier.c in the Linux kernel through 5.12.1 performs undesirable speculative loads, leading
    to disclosure of stack content via side-channel attacks, aka CID-801c6058d14a. The specific concern is not
    protecting the BPF stack area against speculative loads. Also, the BPF stack can contain uninitialized
    data that might represent sensitive information previously operated on by the kernel. (CVE-2021-31829)

  - net/bluetooth/hci_request.c in the Linux kernel through 5.12.2 has a race condition for removal of the HCI
    controller. (CVE-2021-32399)

  - In the Linux kernel before 5.12.4, net/bluetooth/hci_event.c has a use-after-free when destroying an
    hci_chan, aka CID-5c4c8c954409. This leads to writing an arbitrary value. (CVE-2021-33034)

  - kernel/bpf/verifier.c in the Linux kernel through 5.12.7 enforces incorrect limits for pointer arithmetic
    operations, aka CID-bb01a1bba579. This can be abused to perform out-of-bounds reads and writes in kernel
    memory, leading to local privilege escalation to root. In particular, there is a corner case where the off
    reg causes a masking direction change, which then results in an incorrect final aux->alu_limit.
    (CVE-2021-33200)

  - fs/seq_file.c in the Linux kernel 3.16 through 5.13.x before 5.13.4 does not properly restrict seq buffer
    allocations, leading to an integer overflow, an Out-of-bounds Write, and escalation to root by an
    unprivileged user, aka CID-8cae8cd89f05. (CVE-2021-33909)

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-5018-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:H/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:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-33909");

  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:"2021/05/06");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/07/20");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/07/21");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:esm");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1078-oracle");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1092-raspi2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1097-kvm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1106-gcp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1109-aws");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1109-snapdragon");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1121-azure");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-151-generic");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-151-generic-lpae");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-151-lowlatency");
  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:"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 (! ('16.04' >< os_release || '18.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 16.04 / 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 = {
  '16.04': {
    '4.15.0': {
      'generic': '4.15.0-151',
      'lowlatency': '4.15.0-151',
      'oracle': '4.15.0-1078',
      'gcp': '4.15.0-1106',
      'aws': '4.15.0-1109',
      'azure': '4.15.0-1121'
    }
  },
  '18.04': {
    '4.15.0': {
      'generic': '4.15.0-151',
      'generic-lpae': '4.15.0-151',
      'lowlatency': '4.15.0-151',
      'oracle': '4.15.0-1078',
      'raspi2': '4.15.0-1092',
      'kvm': '4.15.0-1097',
      'gcp': '4.15.0-1106',
      'snapdragon': '4.15.0-1109',
      'azure': '4.15.0-1121'
    }
  }
};

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-5018-1');
}

if (get_one_kb_item('Host/ksplice/kernel-cves'))
{
  var cve_list = make_list('CVE-2020-24586', 'CVE-2020-24587', 'CVE-2020-26139', 'CVE-2020-26147', 'CVE-2020-26558', 'CVE-2021-0129', 'CVE-2021-23134', 'CVE-2021-31829', 'CVE-2021-32399', 'CVE-2021-33034', 'CVE-2021-33200', 'CVE-2021-33909');
  if (ksplice_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for USN-5018-1');
  }
  else
  {
    extra = extra + ksplice_reporting_text();
  }
}
if (extra) {
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : extra
  );
  exit(0);
}