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("1.15");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/01/09");

  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.

  - Systems with microprocessors utilizing speculative execution and indirect branch prediction may allow
    unauthorized disclosure of information to an attacker with local user access via a side-channel analysis.
    (CVE-2017-5715)

  - A security flaw was found in the chap_server_compute_md5() function in the ISCSI target code in the Linux
    kernel in a way an authentication request from an ISCSI initiator is processed. An unauthenticated remote
    attacker can cause a stack buffer overflow and smash up to 17 bytes of the stack. The attack requires the
    iSCSI target to be enabled on the victim host. Depending on how the target's code was built (i.e.
    depending on a compiler, compile flags and hardware architecture) an attack may lead to a system crash and
    thus to a denial-of-service or possibly to a non-authorized access to data exported by an iSCSI target.
    Due to the nature of the flaw, privilege escalation cannot be fully ruled out, although we believe it is
    highly unlikely. Kernel versions 4.18.x, 4.14.x and 3.10.x are believed to be vulnerable. (CVE-2018-14633)

  - The spectre_v2_select_mitigation function in arch/x86/kernel/cpu/bugs.c in the Linux kernel before 4.18.1
    does not always fill RSB upon a context switch, which makes it easier for attackers to conduct userspace-
    userspace spectreRSB attacks. (CVE-2018-15572)

  - arch/x86/kernel/paravirt.c in the Linux kernel before 4.18.1 mishandles certain indirect calls, which
    makes it easier for attackers to conduct Spectre-v2 attacks against paravirtual guests. (CVE-2018-15594)

  - An issue was discovered in the Linux kernel through 4.18.8. The vmacache_flush_all function in
    mm/vmacache.c mishandles sequence number overflows. An attacker can trigger a use-after-free (and possibly
    gain privileges) via certain thread creation, map, unmap, invalidation, and dereference operations.
    (CVE-2018-17182)

  - Systems with microprocessors utilizing speculative execution and speculative execution of memory reads
    before the addresses of all prior memory writes are known may allow unauthorized disclosure of information
    to an attacker with local user access via a side-channel analysis, aka Speculative Store Bypass (SSB),
    Variant 4. (CVE-2018-3639)

  - Memory leak in the irda_bind function in net/irda/af_irda.c and later in
    drivers/staging/irda/net/af_irda.c in the Linux kernel before 4.17 allows local users to cause a denial of
    service (memory consumption) by repeatedly binding an AF_IRDA socket. (CVE-2018-6554)

  - The irda_setsockopt function in net/irda/af_irda.c and later in drivers/staging/irda/net/af_irda.c in the
    Linux kernel before 4.17 allows local users to cause a denial of service (ias_object use-after-free and
    system crash) or possibly have unspecified other impact via an AF_IRDA socket. (CVE-2018-6555)

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 = 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);
}