Siemens SIMATIC S7-1500 Excessive Iteration (CVE-2023-3817)

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

include('compat.inc');

if (description)
{
  script_id(504024);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/03/05");

  script_cve_id("CVE-2023-3817");

  script_name(english:"Siemens SIMATIC S7-1500 Excessive Iteration (CVE-2023-3817)");

  script_set_attribute(attribute:"synopsis", value:
"The remote OT asset is affected by a vulnerability.");
  script_set_attribute(attribute:"description", value:
"Issue summary: Checking excessively long DH keys or parameters may be
very slow. Impact summary: Applications that use the functions
DH_check(), DH_check_ex() or EVP_PKEY_param_check() to check a DH key
or DH parameters may experience long delays. Where the key or
parameters that are being checked have been obtained from an untrusted
source this may lead to a Denial of Service. The function DH_check()
performs various checks on DH parameters. After fixing CVE-2023-3446
it was discovered that a large q parameter value can also trigger an
overly long computation during some of these checks. A correct q
value, if present, cannot be larger than the modulus p parameter, thus
it is unnecessary to perform these checks if q is larger than p. An
application that calls DH_check() and supplies a key or parameters
obtained from an untrusted source could be vulnerable to a Denial of
Service attack. The function DH_check() is itself called by a number
of other OpenSSL functions. An application calling any of those other
functions may similarly be affected. The other functions affected by
this are DH_check_ex() and EVP_PKEY_param_check(). Also vulnerable are
the OpenSSL dhparam and pkeyparam command line applications when using
the -check option. The OpenSSL SSL/TLS implementation is not
affected by this issue. The OpenSSL 3.0 and 3.1 FIPS providers are not
affected by this issue.

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-099606.pdf");
  script_set_attribute(attribute:"see_also", value:"https://cert-portal.siemens.com/productcert/html/ssa-398330.html");
  script_set_attribute(attribute:"see_also", value:"https://cert-portal.siemens.com/productcert/pdf/ssa-943925.pdf");
  script_set_attribute(attribute:"see_also", value:"https://cert-portal.siemens.com/productcert/html/ssa-915275.html");
  script_set_attribute(attribute:"see_also", value:"https://support.industry.siemens.com/cs/ww/en/view/109826954/");
  script_set_attribute(attribute:"see_also", value:"https://support.industry.siemens.com/cs/ww/en/view/109975745/");
  script_set_attribute(attribute:"see_also", value:"https://support.industry.siemens.com/cs/ww/en/view/109478459/");
  script_set_attribute(attribute:"see_also", value:"https://support.industry.siemens.com/cs/ww/en/view/109825816/");
  script_set_attribute(attribute:"solution", value:
"Refer to the vendor advisory.");
  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:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2023-3817");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_cwe_id(834);

  script_set_attribute(attribute:"vuln_publication_date", value:"2023/11/14");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/11/14");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/11/13");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:siemens:simatic_s7-1500_cpu_firmware:3.1.5");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:siemens:siplus_s7-1500_cpu_firmware:3.1.5");
  script_set_attribute(attribute:"generated_plugin", value:"former");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2025-2026 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_s7-1500_cpu_firmware:3.1.5" :
        {"versionEndExcluding" : "3.1.5", "versionStartIncluding" : "3.1.0", "family" : "S71500", "orderNumbers" : ['6ES7518-4AX00-1AB0', '6ES7518-4FX00-1AC0', '6ES7518-4AX00-1AC0', '6ES7518-4FX00-1AB0']},
    "cpe:/o:siemens:siplus_s7-1500_cpu_firmware:3.1.5" :
        {"versionEndExcluding" : "3.1.5", "versionStartIncluding" : "3.1.0", "family" : "S71500", "orderNumbers" : ['6AG1518-4AX00-4AC0']}
};

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