Linux Distros Unpatched Vulnerability : CVE-2020-17049

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

include('compat.inc');

if (description)
{
  script_id(223385);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/10/29");

  script_cve_id("CVE-2020-17049");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2020-17049");

  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.

  - A security feature bypass vulnerability exists in the way Key Distribution Center (KDC) determines if a
    service ticket can be used for delegation via Kerberos Constrained Delegation (KCD). To exploit the
    vulnerability, a compromised service that is configured to use KCD could tamper with a service ticket that
    is not valid for delegation to force the KDC to accept it. The update addresses this vulnerability by
    changing how the KDC validates service tickets used with KCD. (CVE-2020-17049)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/cve-2020-17049");
  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:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:U/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-17049");

  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:"2020/11/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/03/04");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:centos:centos:7");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:7");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:krb5");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:krb5-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:krb5-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:krb5-pkinit");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:krb5-server");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:krb5-server-ldap");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:krb5-workstation");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:libkadm5");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:krb5");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:krb5-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:krb5-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:krb5-pkinit");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:krb5-server");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:krb5-server-ldap");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:krb5-workstation");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:libkadm5");
  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("set_linux_os_id.nasl", "ssh_get_info2.nasl");
  script_require_keys("Host/OS/identifier", "Host/cpu", "Host/local_checks_enabled", "global_settings/vendor_unpatched");
  script_require_ports("Host/OS/CentOS Linux-7", "Host/OS/Red Hat Enterprise Linux-7");

  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/CentOS/rpm-list")) && empty_or_null(get_one_kb_item("Host/RedHat/rpm-list"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "CentOS Linux-7": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "7",
        "pkgs": [
          {"reference": "krb5"},
          {"reference": "krb5-devel"},
          {"reference": "krb5-libs"},
          {"reference": "krb5-pkinit"},
          {"reference": "krb5-server"},
          {"reference": "krb5-server-ldap"},
          {"reference": "krb5-workstation"},
          {"reference": "libkadm5"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-7": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "7",
        "pkgs": [
          {"reference": "krb5"},
          {"reference": "krb5-devel"},
          {"reference": "krb5-libs"},
          {"reference": "krb5-pkinit"},
          {"reference": "krb5-server"},
          {"reference": "krb5-server-ldap"},
          {"reference": "krb5-workstation"},
          {"reference": "libkadm5"}
        ]
      }
    ]
  }
};

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_HOLE,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}