Siemens SIMATIC Controller Web Servers Uncaught Exception (CVE-2020-15796)

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

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(500454);
  script_version("1.9");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/09/04");

  script_cve_id("CVE-2020-15796");
  script_xref(name:"ICSA", value:"20-343-09");

  script_name(english:"Siemens SIMATIC Controller Web Servers Uncaught Exception (CVE-2020-15796)");

  script_set_attribute(attribute:"synopsis", value:
"The remote OT asset is affected by a vulnerability.");
  script_set_attribute(attribute:"description", value:
"A vulnerability has been identified in SIMATIC ET 200SP Open Controller (incl. SIPLUS variants) (V20.8), SIMATIC S7-1500
Software Controller (V20.8). The web server of the affected products contains a vulnerability that could allow a remote
attacker to trigger a denial-of-service condition by sending a specially crafted HTTP request.  

This plugin only works
with Tenable.ot. Please visit https://www.tenable.com/products/tenable-ot for more information.");
  script_set_attribute(attribute:"see_also", value:"https://cert-portal.siemens.com/productcert/pdf/ssa-700697.pdf");
  script_set_attribute(attribute:"see_also", value:"https://www.cisa.gov/news-events/ics-advisories/icsa-20-343-09");
  script_set_attribute(attribute:"solution", value:
"The following text was originally created by the Cybersecurity and Infrastructure Security Agency (CISA). The original
can be found at CISA.gov.

Siemens has released updates for the affected products and recommends updating to the latest version:

- SIMATIC ET 200SP Open Controller (incl. SIPLUS variants): Update to v21.8
- SIMATIC S7-1500 Software Controller: Update to v21.8

Siemens notes that if the PC Station web server does not restart automatically, a Windows reboot is required. This can
be done while the control system is running as the PLC control functionality is not affected.

As a general security measure, Siemens strongly recommends users protect network access to devices with appropriate
mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends users configure the
environment according to Siemens’ operational guidelines for industrial security and follow the recommendations in the
product manuals.

For more information, please see Siemens Security Advisory SSA-700697");
  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:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-15796");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_cwe_id(248);

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/12/14");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/12/14");
  script_set_attribute(attribute:"plugin_publication_date", value:"2022/02/07");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:siemens:simatic_et_200sp_open_controller_firmware");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:siemens:simatic_s7-1500_software_controller_firmware");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Tenable.ot");

  script_copyright(english:"This script is Copyright (C) 2022-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("tenable_ot_api_integration.nasl");
  script_require_keys("Tenable.ot/Siemens");

  exit(0);
}


include('tenable_ot_cve_funcs.inc');

get_kb_item_or_exit('Tenable.ot/Siemens');

var asset = tenable_ot::assets::get(vendor:'Siemens');

var vuln_cpes = {
    "cpe:/o:siemens:simatic_et_200sp_open_controller_firmware" :
        {"versionEndIncluding" : "20.8", "family" : "ET200SP"},
    "cpe:/o:siemens:simatic_s7-1500_software_controller_firmware" :
        {"versionEndIncluding" : "20.8", "family" : "S71500"}
};

tenable_ot::cve::compare_and_report(asset:asset, cpes:vuln_cpes, severity:SECURITY_WARNING);