Citrix NetScaler Authentication Bypass Vulnerability (CTX227928)

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

include("compat.inc");

if (description)
{
  script_id(103467);
  script_version("1.5");
  script_cvs_date("Date: 2019/11/12");

  script_cve_id("CVE-2017-14602");
  script_bugtraq_id(100980);

  script_name(english:"Citrix NetScaler Authentication Bypass Vulnerability (CTX227928)");
  script_summary(english:"Checks the Citrix NetScaler version.");

  script_set_attribute(attribute:"synopsis", value:
"The remote device is affected by an authentication 
bypass vulnerability.");
  script_set_attribute(attribute:"description", value:
"The remote Citrix NetScaler device is affected by an 
authentication bypass vulnerability in the Application Delivery 
Controller (ADC) and the Gateway Management Interface.");
  script_set_attribute(attribute:"see_also", value:"https://support.citrix.com/article/CTX227928");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Citrix NetScaler ADC and Gateway version 10.1 build
135.18 / 10.5 build 66.9 / 10.5e build 60.7010.e / 11.0 build
70.16 / 12.0 build 41.24 or 53.13 or later.");
  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:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:H/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-2017-14602");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/09/25");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/09/25");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/09/26");

  script_set_attribute(attribute:"plugin_type", value:"combined");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:citrix:netscaler_application_delivery_controller_firmware");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:citrix:netscaler_access_gateway_firmware");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"CGI abuses");

  script_copyright(english:"This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("citrix_netscaler_detect.nbin");
  script_require_keys("Host/NetScaler/Detected");

  exit(0);
}

include("audit.inc");
include("global_settings.inc");
include("misc_func.inc");

app_name = "Citrix NetScaler";
version = get_kb_item_or_exit("Host/NetScaler/Version");
build = get_kb_item("Host/NetScaler/Build");
enhanced = get_kb_item("Host/NetScaler/Enhanced");
fixed_build = NULL;

if (isnull(build)) exit(0, "The build number of " + app_name + " " + version + " could not be determined.");

display_version = version + "-" + build;
version = version + "." + build;

if (!enhanced)
{
  # non-enhanced builds
  if (version =~ "^10\.1" && ver_compare(ver:build, fix:"135.18") == -1)
  {
    fixed_build = "135.18";
  }
  else if (version =~ "^10\.5" && ver_compare(ver:build, fix:"66.9") == -1)
  {
    fixed_build = "66.9";
  }
  else if (version =~ "^11\.0" && ver_compare(ver:build, fix:"70.16") == -1)
  {
    fixed_build = "70.16";
  }
  else if (version =~ "^11\.1" && ver_compare(ver:build, fix:"55.13") == -1)
  {
    fixed_build = "11.1";
  }
  else if (version =~ "^12\.0" && ver_compare(ver:build, fix:"53.13") == -1)
  {
    # Also check if the build is 41.24 as that is not affected
    if (build == "41.24")
      audit(AUDIT_INST_VER_NOT_VULN, app_name, display_version);
    else
      fixed_build = "53.13";
  }

}
else
{
  # Enhanced build
  display_version = display_version + ".e";
  build = str_replace(string:build, find:'e', replace:'');
  if (version =~ "^10\.5" && ver_compare(ver:build, fix:"60.7010") == -1)
  {
    fixed_build = "60.7010.e";
  }
  build = build+".e";
}

if (isnull(fixed_build))
{
  audit(AUDIT_INST_VER_NOT_VULN, app_name, display_version);
}

report =
   '\n  Installed version : ' + display_version +
   '\n  Installed build   : ' + build +
   '\n  Fixed build       : ' + fixed_build +
   '\n';

security_report_v4(port:0, severity:SECURITY_HOLE, extra:report);