Siemens SIMATIC S7-1500 TM MFP BIOS Integer Overflow or Wraparound (CVE-2021-35942)

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

include('compat.inc');

if (description)
{
  script_id(502942);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/11/14");

  script_cve_id("CVE-2021-35942");
  script_xref(name:"ICSA", value:"23-166-10");

  script_name(english:"Siemens SIMATIC S7-1500 TM MFP BIOS Integer Overflow or Wraparound (CVE-2021-35942)");

  script_set_attribute(attribute:"synopsis", value:
"The remote OT asset is affected by a vulnerability.");
  script_set_attribute(attribute:"description", value:
"The wordexp function in the GNU C Library (aka glibc) through 2.33 may
crash or read arbitrary memory in parse_param (in posix/wordexp.c)
when called with an untrusted, crafted pattern, potentially resulting
in a denial of service or disclosure of information. This occurs
because atoi was used but strtoul should have been used to ensure
correct calculations.

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-831302.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://support.industry.siemens.com/cs/ww/en/view/109945851/");
  script_set_attribute(attribute:"see_also", value:"https://www.cisa.gov/news-events/ics-advisories/icsa-23-166-10");
  script_set_attribute(attribute:"solution", value:
"Refer to the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/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:H/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-35942");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_cwe_id(190);

  script_set_attribute(attribute:"vuln_publication_date", value:"2023/06/13");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/06/13");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/02/25");

  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:simatic_s7-1500_tm_mfp");
  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 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_tm_mfp" :
        {"versionEndExcluding" : "1.3", "family" : "S71500", "orderNumbers": ["6ES7558-1AA00-0AB0"]},
    "cpe:/o:siemens:simatic_s7-1500_cpu_firmware:3.1.5" :
        {"versionEndExcluding" : "3.1.5", "versionStartIncluding" : "3.1.0", "family" : "S71500", "orderNumbers" : ['6ES7518-4FX00-1AC0', '6ES7518-4AX00-1AC0', '6ES7518-4AX00-1AB0', '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_WARNING);