Linux Distros Unpatched Vulnerability : CVE-2021-3738

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(258192);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/08/30");

  script_cve_id("CVE-2021-3738");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2021-3738");

  script_set_attribute(attribute:"synopsis", value:
"The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be
patched.");
  script_set_attribute(attribute:"description", value:
"The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied
patch available.

  - In DCE/RPC it is possible to share the handles (cookies for resource state) between multiple connections
    via a mechanism called 'association groups'. These handles can reference connections to our sam.ldb
    database. However while the database was correctly shared, the user credentials state was only pointed at,
    and when one connection within that association group ended, the database would be left pointing at an
    invalid 'struct session_info'. The most likely outcome here is a crash, but it is possible that the use-
    after-free could instead allow different user state to be pointed at and this might allow more privileged
    access. (CVE-2021-3738)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2021-3738");
  script_set_attribute(attribute:"solution", value:
"There is no known solution at this time.");
  script_set_attribute(attribute:"agent", value:"unix");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-3738");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/11/09");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/08/30");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:14.04:-:lts");
  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:samba");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2025 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.nasl", "set_linux_os_id.nasl");
  script_require_keys("Host/cpu", "Host/local_checks_enabled", "global_settings/vendor_unpatched", "Host/OS/identifier");
  script_require_ports("Host/OS/Ubuntu Linux-14.04", "Host/OS/Ubuntu Linux-16.04", "Host/OS/Ubuntu Linux-18.04");

  exit(0);
}

if (!get_kb_item("global_settings/vendor_unpatched")) exit(0, "Unpatched Vulnerabilities Detection not active.");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (empty_or_null(get_one_kb_item("Host/Debian/dpkg-l"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Ubuntu Linux-14.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14.04",
        "pkgs": [
          {"reference": "libnss-winbind"},
          {"reference": "libpam-smbpass"},
          {"reference": "libpam-winbind"},
          {"reference": "libparse-pidl-perl"},
          {"reference": "libsmbclient"},
          {"reference": "libsmbclient-dev"},
          {"reference": "libsmbsharemodes-dev"},
          {"reference": "libsmbsharemodes0"},
          {"reference": "libwbclient-dev"},
          {"reference": "libwbclient0"},
          {"reference": "python-samba"},
          {"reference": "registry-tools"},
          {"reference": "samba"},
          {"reference": "samba-common"},
          {"reference": "samba-common-bin"},
          {"reference": "samba-dbg"},
          {"reference": "samba-dev"},
          {"reference": "samba-doc"},
          {"reference": "samba-dsdb-modules"},
          {"reference": "samba-libs"},
          {"reference": "samba-testsuite"},
          {"reference": "samba-vfs-modules"},
          {"reference": "smbclient"},
          {"reference": "winbind"}
        ]
      }
    ]
  },
  "Ubuntu Linux-16.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "16.04",
        "pkgs": [
          {"reference": "ctdb"},
          {"reference": "libnss-winbind"},
          {"reference": "libpam-winbind"},
          {"reference": "libparse-pidl-perl"},
          {"reference": "libsmbclient"},
          {"reference": "libsmbclient-dev"},
          {"reference": "libwbclient-dev"},
          {"reference": "libwbclient0"},
          {"reference": "python-samba"},
          {"reference": "registry-tools"},
          {"reference": "samba"},
          {"reference": "samba-common"},
          {"reference": "samba-common-bin"},
          {"reference": "samba-dbg"},
          {"reference": "samba-dev"},
          {"reference": "samba-dsdb-modules"},
          {"reference": "samba-libs"},
          {"reference": "samba-testsuite"},
          {"reference": "samba-vfs-modules"},
          {"reference": "smbclient"},
          {"reference": "winbind"}
        ]
      }
    ]
  },
  "Ubuntu Linux-18.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "18.04",
        "pkgs": [
          {"reference": "ctdb"},
          {"reference": "libnss-winbind"},
          {"reference": "libpam-winbind"},
          {"reference": "libparse-pidl-perl"},
          {"reference": "libsmbclient"},
          {"reference": "libsmbclient-dev"},
          {"reference": "libwbclient-dev"},
          {"reference": "libwbclient0"},
          {"reference": "python-samba"},
          {"reference": "registry-tools"},
          {"reference": "samba"},
          {"reference": "samba-common"},
          {"reference": "samba-common-bin"},
          {"reference": "samba-dev"},
          {"reference": "samba-dsdb-modules"},
          {"reference": "samba-libs"},
          {"reference": "samba-testsuite"},
          {"reference": "samba-vfs-modules"},
          {"reference": "smbclient"},
          {"reference": "winbind"}
        ]
      }
    ]
  }
};

var distro_constraints_values = linux_unpatched::get_distro_constraints(distro_constraints_arr:distro_constraints_array);
if (empty_or_null(distro_constraints_values)) audit(AUDIT_HOST_NOT, 'affected');
var report = linux_unpatched::check_unpatched_constraints(distro_constraints_values:distro_constraints_values);

if (!empty_or_null(report))
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}