Ubuntu 20.04 LTS : Samba regressions (USN-5142-2)

#%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-5142-2. 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(155892);
  script_version("1.6");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/08/28");
  script_xref(name:"USN", value:"5142-2");

  script_name(english:"Ubuntu 20.04 LTS : Samba regressions (USN-5142-2)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 20.04 LTS host has packages installed that are affected by a vulnerability as referenced in the
USN-5142-2 advisory.

    USN-5142-1 fixed vulnerabilities in Samba. Some of the upstream changes introduced regressions in name
    mapping and backups.

    Please see the following upstream bugs for more information:
    https://bugzilla.samba.org/show_bug.cgi?id=14901 https://bugzilla.samba.org/show_bug.cgi?id=14918

    This update fixes the problem.

    Original advisory details:

    Stefan Metzmacher discovered that Samba incorrectly handled SMB1 client

    connections. A remote attacker could possibly use this issue to downgrade

    connections to plaintext authentication. (CVE-2016-2124)

    Andrew Bartlett discovered that Samba incorrectly mapping domain users to

    local users. An authenticated attacker could possibly use this issue to

    become root on domain members. (CVE-2020-25717)

    Andrew Bartlett discovered that Samba did not correctly sandbox Kerberos

    tickets issues by an RODC. An RODC could print administrator tickets,

    contrary to expectations. (CVE-2020-25718)

    Andrew Bartlett discovered that Samba incorrectly handled Kerberos tickets.

    Delegated administrators could possibly use this issue to impersonate

    accounts, leading to total domain compromise. (CVE-2020-25719)

    Andrew Bartlett discovered that Samba did not provide stable AD

    identifiers to Kerberos acceptors. (CVE-2020-25721)

    Andrew Bartlett discovered that Samba did not properly check sensitive

    attributes. An authenticated attacker could possibly use this issue to

    escalate privileges. (CVE-2020-25722)

    Stefan Metzmacher discovered that Samba incorrectly handled certain large

    DCE/RPC requests. A remote attacker could possibly use this issue to

    bypass signature requirements. (CVE-2021-23192)

    William Ross discovered that Samba incorrectly handled memory. A remote

    attacker could use this issue to cause Samba to crash, resulting in a

    denial of service, or possibly escalate privileges. (CVE-2021-3738)

    Joseph Sutton discovered that Samba incorrectly handled certain TGS

    requests. An authenticated attacker could possibly use this issue to cause

    Samba to crash, resulting in a denial of service. (CVE-2021-3671)

    The fix for CVE-2020-25717 results in possible behaviour changes that could

    affect certain environments. Please see the upstream advisory for more

    information:

    https://www.samba.org/samba/security/CVE-2020-25717.html

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-5142-2");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_attribute(attribute:"risk_factor", value:"None");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/12/06");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/12/06");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/12/07");

  script_set_attribute(attribute:"plugin_type", value:"local");
  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: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: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:python3-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_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");
  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 (! ('20.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 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 pkgs = [
    {'osver': '20.04', 'pkgname': 'ctdb', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'libnss-winbind', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'libpam-winbind', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'libsmbclient', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'libsmbclient-dev', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'libwbclient-dev', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'libwbclient0', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'python3-samba', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'registry-tools', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'samba', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'samba-common', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'samba-common-bin', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'samba-dev', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'samba-dsdb-modules', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'samba-libs', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'samba-testsuite', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'samba-vfs-modules', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'smbclient', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'},
    {'osver': '20.04', 'pkgname': 'winbind', 'pkgver': '2:4.13.14+dfsg-0ubuntu0.20.04.3'}
];

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_NOTE,
    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 / libsmbclient / etc');
}