Ubuntu 16.04 LTS : Linux kernel vulnerabilities (USN-4391-1)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-4391-1. 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(137301);
  script_version("1.8");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/01/09");

  script_cve_id(
    "CVE-2019-19319",
    "CVE-2020-0543",
    "CVE-2020-10751",
    "CVE-2020-12114",
    "CVE-2020-12464",
    "CVE-2020-12769",
    "CVE-2020-12826",
    "CVE-2020-1749"
  );
  script_xref(name:"USN", value:"4391-1");

  script_name(english:"Ubuntu 16.04 LTS : Linux kernel vulnerabilities (USN-4391-1)");

  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 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in
the USN-4391-1 advisory.

  - In the Linux kernel before 5.2, a setxattr operation, after a mount of a crafted ext4 image, can cause a
    slab-out-of-bounds write access because of an ext4_xattr_set_entry use-after-free in fs/ext4/xattr.c when
    a large old_size value is used in a memset call, aka CID-345c0dbf3a30. (CVE-2019-19319)

  - Incomplete cleanup from specific special register read operations in some Intel(R) Processors may allow an
    authenticated user to potentially enable information disclosure via local access. (CVE-2020-0543)

  - A flaw was found in the Linux kernels SELinux LSM hook implementation before version 5.7, where it
    incorrectly assumed that an skb would only contain a single netlink message. The hook would incorrectly
    only validate the first netlink message in the skb and allow or deny the rest of the messages within the
    skb with the granted permission without further processing. (CVE-2020-10751)

  - A pivot_root race condition in fs/namespace.c in the Linux kernel 4.4.x before 4.4.221, 4.9.x before
    4.9.221, 4.14.x before 4.14.178, 4.19.x before 4.19.119, and 5.x before 5.3 allows local users to cause a
    denial of service (panic) by corrupting a mountpoint reference counter. (CVE-2020-12114)

  - usb_sg_cancel in drivers/usb/core/message.c in the Linux kernel before 5.6.8 has a use-after-free because
    a transfer occurs without a reference, aka CID-056ad39ee925. (CVE-2020-12464)

  - An issue was discovered in the Linux kernel before 5.4.17. drivers/spi/spi-dw.c allows attackers to cause
    a panic via concurrent calls to dw_spi_irq and dw_spi_transfer_one, aka CID-19b61392c5a8. (CVE-2020-12769)

  - A signal access-control issue was discovered in the Linux kernel before 5.6.5, aka CID-7395ea4e65c2.
    Because exec_id in include/linux/sched.h is only 32 bits, an integer overflow can interfere with a
    do_notify_parent protection mechanism. A child process can send an arbitrary signal to a parent process in
    a different security domain. Exploitation limitations include the amount of elapsed time before an integer
    overflow occurs, and the lack of scenarios where signals to a parent process present a substantial
    operational threat. (CVE-2020-12826)

  - A flaw was found in the Linux kernel's implementation of some networking protocols in IPsec, such as VXLAN
    and GENEVE tunnels over IPv6. When an encrypted tunnel is created between two hosts, the kernel isn't
    correctly routing tunneled data over the encrypted link; rather sending the data unencrypted. This would
    allow anyone in between the two endpoints to read the traffic unencrypted. The main threat from this
    vulnerability is to data confidentiality. (CVE-2020-1749)

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-4391-1");
  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:POC/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:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-12464");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2020-1749");

  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:"2019/11/27");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/06/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/06/10");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-1075-kvm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-1109-aws");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-1134-raspi2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-1138-snapdragon");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-184-generic");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-184-generic-lpae");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-184-lowlatency");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-184-powerpc-e500mc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-184-powerpc-smp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-184-powerpc64-emb");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-184-powerpc64-smp");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-: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 (! ('16.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 16.04', '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': {
    '4.4.0': {
      'generic': '4.4.0-184',
      'generic-lpae': '4.4.0-184',
      'lowlatency': '4.4.0-184',
      'powerpc-e500mc': '4.4.0-184',
      'powerpc-smp': '4.4.0-184',
      'powerpc64-emb': '4.4.0-184',
      'powerpc64-smp': '4.4.0-184',
      'kvm': '4.4.0-1075',
      'aws': '4.4.0-1109',
      'raspi2': '4.4.0-1134',
      'snapdragon': '4.4.0-1138'
    }
  }
};

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-4391-1');
}

if (get_one_kb_item('Host/ksplice/kernel-cves'))
{
  var cve_list = make_list('CVE-2019-19319', 'CVE-2020-0543', 'CVE-2020-1749', 'CVE-2020-10751', 'CVE-2020-12114', 'CVE-2020-12464', 'CVE-2020-12769', 'CVE-2020-12826');
  if (ksplice_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for USN-4391-1');
  }
  else
  {
    extra = extra + ksplice_reporting_text();
  }
}
if (extra) {
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : extra
  );
  exit(0);
}