VMware vCenter Server 6.5 / 6.7 / 7.0 DoS (VMSA-2020-0018)

#
# (C) Tenable Network Security, Inc.
#

include('compat.inc');

if (description)
{
  script_id(140040);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/11/02");

  script_cve_id("CVE-2020-3976");
  script_xref(name:"IAVA", value:"2020-A-0386");

  script_name(english:"VMware vCenter Server 6.5 / 6.7 / 7.0 DoS (VMSA-2020-0018)");

  script_set_attribute(attribute:"synopsis", value:
"A virtualization management application installed on the remote host is affected by a denial of service vulnerability.");
  script_set_attribute(attribute:"description", value:
"The version of VMware vCenter Server installed on the remote host is 6.5 prior to 6.5u3k, 6.7 prior to 6.7u3j or 7.0
prior to 7.0.0b. It is, therefore, affected by a denial of service vulnerability (DoS) in the authentication service. An
unauthenticated, remote attacker can exploit this issue to exhaust memory resources resulting in a degradation of
performance condition while the attack is sustained.                              

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://www.vmware.com/security/advisories/VMSA-2020-0018.html");
  script_set_attribute(attribute:"solution", value:
"Upgrade to VMware vCenter Server 6.5u3k, 6.7u3j, 7.0.0b or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/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:N/UI:N/S:U/C:N/I:N/A:L");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-3976");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/08/20");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/08/20");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/08/28");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:vmware:vcenter_server");
  script_set_attribute(attribute:"stig_severity", value:"II");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("vmware_vcenter_detect.nbin");
  script_require_keys("Host/VMware/vCenter", "Host/VMware/version", "Host/VMware/release");
  script_require_ports("Services/www", 80, 443);

  exit(0);
}

fixes = make_array(
  '6.5', '16613358',
  '6.7', '16708996',
  '7.0', '16749653'
);

port = get_kb_item_or_exit('Host/VMware/vCenter');
version = get_kb_item_or_exit('Host/VMware/version');
release = get_kb_item_or_exit('Host/VMware/release');

# Extract and verify the build number
build = ereg_replace(pattern:"^VMware vCenter Server [0-9\\.]+ build-([0-9]+)$", string:release, replace:"\1");
if (build !~ "^[0-9]+$") audit(AUDIT_UNKNOWN_BUILD, 'VMware vCenter 6.5 / 6.7 / 7.0');

match = pregmatch(pattern:"^VMware vCenter ([0-9]+\.[0-9]+).*$", string:version);
if (isnull(match)) audit(AUDIT_OS_NOT, 'VMware vCenter 6.5 / 6.7 / 7.0');

ver = match[1];
if (ver !~ "^(7\.0|6\.(5|7))$") audit(AUDIT_OS_NOT, 'VMware vCenter 6.5 / 6.7 / 7.0');

fixed_build = int(fixes[ver]);
if (empty_or_null(fixed_build)) audit(AUDIT_VER_FORMAT, ver);

release = release - 'VMware vCenter Server ';
if (build >= fixed_build) 
  audit(AUDIT_LISTEN_NOT_VULN, 'VMware vCenter', port, release);

report = '\n  VMware vCenter version    : ' + ver +
         '\n  Installed build           : ' + build +
         '\n  Fixed build               : ' + fixed_build +
         '\n';

security_report_v4(port:port, severity:SECURITY_WARNING, extra:report);