Cisco ASA Uncontrolled Resource Consumption (CVE-2021-40125)

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

include('compat.inc');

if (description)
{
  script_id(506134);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/07");

  script_cve_id("CVE-2021-40125");

  script_name(english:"Cisco ASA Uncontrolled Resource Consumption (CVE-2021-40125)");

  script_set_attribute(attribute:"synopsis", value:
"The remote OT asset is affected by a vulnerability.");
  script_set_attribute(attribute:"description", value:
"A vulnerability in the Internet Key Exchange Version 2 (IKEv2)
implementation of Cisco Adaptive Security Appliance (ASA) Software and
Cisco Firepower Threat Defense (FTD) Software could allow an
authenticated, remote attacker to trigger a denial of service (DoS)
condition on an affected device. This vulnerability is due to improper
control of a resource. An attacker with the ability to spoof a trusted
IKEv2 site-to-site VPN peer and in possession of valid IKEv2
credentials for that peer could exploit this vulnerability by sending
malformed, authenticated IKEv2 messages to an affected device. A
successful exploit could allow the attacker to trigger a reload of the
device.

This plugin only works with Tenable.ot.
Please visit https://www.tenable.com/products/tenable-ot for more information.");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ikev2-dos-g4cmrr7C
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?0c784582");
  script_set_attribute(attribute:"solution", value:
"Refer to the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:S/C:N/I:N/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:L/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-2021-40125");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_cwe_id(400, 416);

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/10/27");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/10/27");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/06");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:cisco:adaptive_security_appliance_software:9");
  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) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

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

  exit(0);
}


include('tenable_ot_cve_funcs.inc');

get_kb_item_or_exit('Tenable.ot/Cisco');

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

var vuln_cpes = {
    "cpe:/o:cisco:adaptive_security_appliance_software:9.8.0" :
        {"versionEndExcluding" : "9.8.4.40", "versionStartIncluding" : "9.8.0", "family" : "CiscoFirepower"},
    "cpe:/o:cisco:adaptive_security_appliance_software:9.9.0" :
        {"versionEndExcluding" : "9.12.4.30", "versionStartIncluding" : "9.9.0", "family" : "CiscoFirepower"},
    "cpe:/o:cisco:adaptive_security_appliance_software:9.14.0" :
        {"versionEndExcluding" : "9.14.3.9", "versionStartIncluding" : "9.14.0", "family" : "CiscoFirepower"},
    "cpe:/o:cisco:adaptive_security_appliance_software:9.15.0" :
        {"versionEndExcluding" : "9.15.1.17", "versionStartIncluding" : "9.15.0", "family" : "CiscoFirepower"},
    "cpe:/o:cisco:adaptive_security_appliance_software:9.16.0" :
        {"versionEndExcluding" : "9.16.2", "versionStartIncluding" : "9.16.0", "family" : "CiscoFirepower"}
};

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