Ubuntu 16.04 LTS / 18.04 LTS : Linux kernel (Azure) vulnerabilities (USN-3777-3)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-3777-3. 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(118322);
  script_version("1.16");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/08/28");

  script_cve_id(
    "CVE-2017-5715",
    "CVE-2018-14633",
    "CVE-2018-15572",
    "CVE-2018-15594",
    "CVE-2018-17182",
    "CVE-2018-3639",
    "CVE-2018-6554",
    "CVE-2018-6555"
  );
  script_xref(name:"USN", value:"3777-3");

  script_name(english:"Ubuntu 16.04 LTS / 18.04 LTS : Linux kernel (Azure) vulnerabilities (USN-3777-3)");

  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 / 18.04 LTS host has a package installed that is affected by multiple vulnerabilities as
referenced in the USN-3777-3 advisory.

    USN-3777-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 %LTS. This update provides the
    corresponding updates for the Linux kernel for Azure Cloud systems.

    Jann Horn discovered that the vmacache subsystem did not properly handle sequence number overflows,
    leading to a use-after-free vulnerability. A local attacker could use this to cause a denial of service
    (system crash) or execute arbitrary code. (CVE-2018-17182)

    It was discovered that the paravirtualization implementation in the Linux kernel did not properly handle
    some indirect calls, reducing the effectiveness of Spectre v2 mitigations for paravirtual guests. A local
    attacker could use this to expose sensitive information. (CVE-2018-15594)

    It was discovered that microprocessors utilizing speculative execution and prediction of return addresses
    via Return Stack Buffer (RSB) may allow unauthorized memory reads via sidechannel attacks. An attacker
    could use this to expose sensitive information. (CVE-2018-15572)

    Jann Horn discovered that microprocessors utilizing speculative execution and branch prediction may allow
    unauthorized memory reads via sidechannel attacks. This flaw is known as Spectre. A local attacker could
    use this to expose sensitive information, including kernel memory. (CVE-2017-5715)

    It was discovered that a stack-based buffer overflow existed in the iSCSI target implementation of the
    Linux kernel. A remote attacker could use this to cause a denial of service (system crash).
    (CVE-2018-14633)

    Jann Horn and Ken Johnson discovered that microprocessors utilizing speculative execution of a memory read
    may allow unauthorized memory reads via a sidechannel attack. This flaw is known as Spectre Variant 4. A
    local attacker could use this to expose sensitive information, including kernel memory. (CVE-2018-3639)

    It was discovered that a memory leak existed in the IRDA subsystem of the Linux kernel. A local attacker
    could use this to cause a denial of service (kernel memory exhaustion). (CVE-2018-6554)

    It was discovered that a use-after-free vulnerability existed in the IRDA implementation in the Linux
    kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute
    arbitrary code. (CVE-2018-6555)

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-3777-3");
  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: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-2018-14633");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2018-6555");

  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:"in_the_news", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2018/01/04");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/10/23");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/10/23");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1025-azure");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:lts");
  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) 2018-2024 Canonical, Inc. / NASL script (C) 2018-2024 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': {
      'azure': '4.15.0-1025'
    }
  },
  '18.04': {
    '4.15.0': {
      'azure': '4.15.0-1025'
    }
  }
};

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-3777-3');
}

if (get_one_kb_item('Host/ksplice/kernel-cves'))
{
  var cve_list = make_list('CVE-2017-5715', 'CVE-2018-3639', 'CVE-2018-6554', 'CVE-2018-6555', 'CVE-2018-14633', 'CVE-2018-15572', 'CVE-2018-15594', 'CVE-2018-17182');
  if (ksplice_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for USN-3777-3');
  }
  else
  {
    extra = extra + ksplice_reporting_text();
  }
}
if (extra) {
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : extra
  );
  exit(0);
}