Ubuntu 16.04 LTS / 18.04 LTS : Samba vulnerability (USN-4510-1)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-4510-1. 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(140640);
  script_version("1.14");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/08/29");

  script_cve_id("CVE-2020-1472");
  script_xref(name:"USN", value:"4510-1");
  script_xref(name:"IAVA", value:"2020-A-0438-S");
  script_xref(name:"IAVA", value:"0001-A-0647");
  script_xref(name:"CISA-KNOWN-EXPLOITED", value:"2020/09/21");
  script_xref(name:"CISA-NCAS", value:"AA22-011A");
  script_xref(name:"CEA-ID", value:"CEA-2020-0129");
  script_xref(name:"CEA-ID", value:"CEA-2020-0101");
  script_xref(name:"CEA-ID", value:"CEA-2021-0025");
  script_xref(name:"CEA-ID", value:"CEA-2021-0008");
  script_xref(name:"CEA-ID", value:"CEA-2020-0121");
  script_xref(name:"CEA-ID", value:"CEA-2023-0016");

  script_name(english:"Ubuntu 16.04 LTS / 18.04 LTS : Samba vulnerability (USN-4510-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 16.04 LTS / 18.04 LTS host has packages installed that are affected by a vulnerability as referenced
in the USN-4510-1 advisory.

    Tom Tervoort discovered that the Netlogon protocol implemented by Samba incorrectly handled the
    authentication scheme. A remote attacker could use this issue to forge an authentication token and steal
    the credentials of the domain admin.

    This update fixes the issue by changing the server schannel setting to default to yes, instead of
    auto, which will force a secure netlogon channel. This may result in compatibility issues with older
    devices. A future update may allow a finer-grained control over this setting.

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for this issue 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-4510-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/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:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-1472");

  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:"2020/08/17");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/09/17");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/09/17");

  script_set_attribute(attribute:"plugin_type", value:"local");
  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:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:ctdb");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libnss-winbind");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libpam-winbind");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libparse-pidl-perl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libsmbclient");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libsmbclient-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libwbclient-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libwbclient0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python-samba");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:registry-tools");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:samba");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:samba-common");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:samba-common-bin");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:samba-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:samba-dsdb-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:samba-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:samba-testsuite");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:samba-vfs-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:smbclient");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:winbind");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"I");
  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");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}

include('debian_package.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 pkgs = [
    {'osver': '16.04', 'pkgname': 'ctdb', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'libnss-winbind', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'libpam-winbind', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'libparse-pidl-perl', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'libsmbclient', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'libsmbclient-dev', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'libwbclient-dev', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'libwbclient0', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'python-samba', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'registry-tools', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'samba', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'samba-common', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'samba-common-bin', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'samba-dev', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'samba-dsdb-modules', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'samba-libs', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'samba-testsuite', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'samba-vfs-modules', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'smbclient', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '16.04', 'pkgname': 'winbind', 'pkgver': '2:4.3.11+dfsg-0ubuntu0.16.04.30'},
    {'osver': '18.04', 'pkgname': 'ctdb', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'libnss-winbind', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'libpam-winbind', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'libparse-pidl-perl', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'libsmbclient', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'libsmbclient-dev', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'libwbclient-dev', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'libwbclient0', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'python-samba', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'registry-tools', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'samba', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'samba-common', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'samba-common-bin', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'samba-dev', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'samba-dsdb-modules', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'samba-libs', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'samba-testsuite', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'samba-vfs-modules', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'smbclient', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'},
    {'osver': '18.04', 'pkgname': 'winbind', 'pkgver': '2:4.7.6+dfsg~ubuntu-0ubuntu2.19'}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var osver = NULL;
  var pkgname = NULL;
  var pkgver = NULL;
  if (!empty_or_null(package_array['osver'])) osver = package_array['osver'];
  if (!empty_or_null(package_array['pkgname'])) pkgname = package_array['pkgname'];
  if (!empty_or_null(package_array['pkgver'])) pkgver = package_array['pkgver'];
  if (osver && pkgname && pkgver) {
    if (ubuntu_check(osver:osver, pkgname:pkgname, pkgver:pkgver)) flag++;
  }
}

if (flag)
{
  var extra = '';
  extra += ubuntu_report_get();
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : extra
  );
  exit(0);
}
else
{
  var tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'ctdb / libnss-winbind / libpam-winbind / libparse-pidl-perl / etc');
}