Ubuntu 18.04 LTS / 20.04 LTS : Linux kernel vulnerabilities (USN-5137-2)

#%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-5137-2. 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(155222);
  script_version("1.6");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/01/09");

  script_cve_id(
    "CVE-2019-19449",
    "CVE-2020-36385",
    "CVE-2021-3428",
    "CVE-2021-3739",
    "CVE-2021-3743",
    "CVE-2021-3753",
    "CVE-2021-3759",
    "CVE-2021-34556",
    "CVE-2021-35477"
  );
  script_xref(name:"USN", value:"5137-2");

  script_name(english:"Ubuntu 18.04 LTS / 20.04 LTS : Linux kernel vulnerabilities (USN-5137-2)");

  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 / 20.04 LTS host has a package installed that is affected by multiple vulnerabilities as
referenced in the USN-5137-2 advisory.

  - In the Linux kernel 5.0.21, mounting a crafted f2fs filesystem image can lead to slab-out-of-bounds read
    access in f2fs_build_segment_manager in fs/f2fs/segment.c, related to init_min_max_mtime in
    fs/f2fs/segment.c (because the second argument to get_seg_entry is not validated). (CVE-2019-19449)

  - An issue was discovered in the Linux kernel before 5.10. drivers/infiniband/core/ucma.c has a use-after-
    free because the ctx is reached via the ctx_list in some ucma_migrate_id situations where ucma_close is
    called, aka CID-f5449e74802c. (CVE-2020-36385)

  - A flaw was found in the Linux kernel. A denial of service problem is identified if an extent tree is
    corrupted in a crafted ext4 filesystem in fs/ext4/extents.c in ext4_es_cache_extent. Fabricating an
    integer overflow, A local attacker with a special user privilege may cause a system crash problem which
    can lead to an availability threat. (CVE-2021-3428)

  - In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from
    kernel memory via a Speculative Store Bypass side-channel attack because the protection mechanism neglects
    the possibility of uninitialized memory locations on the BPF stack. (CVE-2021-34556)

  - In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from
    kernel memory via a Speculative Store Bypass side-channel attack because a certain preempting store
    operation does not necessarily occur before a store operation that has an attacker-controlled value.
    (CVE-2021-35477)

  - 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)

  - A memory overflow vulnerability was found in the Linux kernel's ipc functionality of the memcg subsystem,
    in the way a user calls the semget function multiple times, creating semaphores. This flaw allows a local
    user to starve the resources, causing a denial of service. The highest threat from this vulnerability is
    to system availability. (CVE-2021-3759)

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-5137-2");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P");
  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:N/UI:R/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-2020-36385");

  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:"2019/12/08");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/11/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/11/11");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  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-5.4.0-1021-bluefield");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.4.0-1046-raspi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.4.0-1055-gke");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.4.0-1057-oracle");
  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 (! ('18.04' >< os_release || '20.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 18.04 / 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 = {
  '18.04': {
    '5.4.0': {
      'raspi': '5.4.0-1046',
      'gke': '5.4.0-1055',
      'oracle': '5.4.0-1057'
    }
  },
  '20.04': {
    '5.4.0': {
      'bluefield': '5.4.0-1021',
      'raspi': '5.4.0-1046',
      'oracle': '5.4.0-1057'
    }
  }
};

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-5137-2');
}

if (get_one_kb_item('Host/ksplice/kernel-cves'))
{
  var cve_list = make_list('CVE-2019-19449', 'CVE-2020-36385', 'CVE-2021-3428', 'CVE-2021-3739', 'CVE-2021-3743', 'CVE-2021-3753', 'CVE-2021-3759', 'CVE-2021-34556', 'CVE-2021-35477');
  if (ksplice_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for USN-5137-2');
  }
  else
  {
    extra = extra + ksplice_reporting_text();
  }
}
if (extra) {
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : extra
  );
  exit(0);
}