ESXi 6.5 / 6.7 / 7.0 Multiple Vulnerabilities (VMSA-2021-0014)

#%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
##

include('deprecated_nasl_level.inc');

include('compat.inc');

if (description)
{
  script_id(151665);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/05/22");

  script_cve_id("CVE-2021-21994", "CVE-2021-21995");
  script_xref(name:"IAVA", value:"2021-A-0312");

  script_name(english:"ESXi 6.5 / 6.7 / 7.0 Multiple Vulnerabilities (VMSA-2021-0014)");

  script_set_attribute(attribute:"synopsis", value:
"The remote VMware ESXi host is missing a security patch and is affected by multiple vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"The remote VMware ESXi host is version 6.5, 6.7 or 7.0 and is affected by multiple vulnerabilities:

  - SFCB (Small Footprint CIM Broker) as used in ESXi has an authentication bypass vulnerability. A malicious actor
    with network access to port 5989 on ESXi may exploit this issue to bypass SFCB authentication by sending a
    specially crafted request. (CVE-2021-21994)

  - OpenSLP as used in ESXi has a denial-of-service vulnerability due a heap out-of-bounds read issue. A malicious
    actor with network access to port 427 on ESXi may be able to trigger a heap out-of-bounds read in OpenSLP service
    resulting in a denial-of-service condition. (CVE-2021-21995)

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-2021-0014.html");
  script_set_attribute(attribute:"solution", value:
"Apply the appropriate patch as referenced in the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/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:N/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-2021-21994");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/07/13");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/03/09");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/07/15");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:vmware:esxi");
  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) 2021-2023 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("vmware_vsphere_detect.nbin", "slp_tcp_detect.nasl", "slp_udp_detect.nasl");
  script_require_keys("Host/VMware/version", "Host/VMware/release");

  exit(0);
}

# checking if slp service is enabled from workaround https://kb.vmware.com/s/article/76372
if (!get_kb_item("Services/slp")) exit(0, "The SLP service is not enabled on the target device.");

var fixes = make_array(
  '6.5', '18071574', # ESXi650-202107001
  '6.7', '17700523', # ESXi670-202103001
  '7.0', '17630552'  # ESXi 7.0 Update 2
);

var rel = get_kb_item_or_exit('Host/VMware/release');
if ('ESXi' >!< rel) audit(AUDIT_OS_NOT, 'ESXi');

var ver = get_kb_item_or_exit('Host/VMware/version');
var port  = get_kb_item_or_exit('Host/VMware/vsphere');

var match = pregmatch(pattern:"^ESXi? ([0-9]+\.[0-9]+).*$", string:ver);
if (isnull(match)) audit(AUDIT_UNKNOWN_BUILD, 'VMware ESXi', '6.5 / 6.7 / 7.0');
ver = match[1];

if (ver !~ "^(7\.0|6\.(5|7))$") audit(AUDIT_OS_NOT, 'ESXi 6.5 / 6.7 / 7.0');

var fixed_build = int(fixes[ver]);

if (empty_or_null(fixed_build)) audit(AUDIT_VER_FORMAT, ver);

match = pregmatch(pattern:"^VMware ESXi.*build-([0-9]+)$", string:rel);
if (isnull(match)) audit(AUDIT_UNKNOWN_BUILD, 'VMware ESXi', '6.5 / 6.7 / 7.0');

var build = int(match[1]);

if (build >= fixed_build) audit(AUDIT_INST_VER_NOT_VULN, 'VMware ESXi', ver + ' build ' + build);

var report = '\n  ESXi version    : ' + ver +
         '\n  Installed build : ' + build +
         '\n  Fixed build     : ' + fixed_build +
         '\n';

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