Cisco ASA Reachable Assertion (CVE-2021-1422)

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

include('compat.inc');

if (description)
{
  script_id(506179);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/07");

  script_cve_id("CVE-2021-1422");

  script_name(english:"Cisco ASA Reachable Assertion (CVE-2021-1422)");

  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 software cryptography module of Cisco Adaptive
Security Appliance (ASA) Software and Cisco Firepower Threat Defense
(FTD) Software could allow an authenticated, remote attacker or an
unauthenticated attacker in a man-in-the-middle position to cause an
unexpected reload of the device that results in a denial of service
(DoS) condition. The vulnerability is due to a logic error in how the
software cryptography module handles specific types of decryption
errors. An attacker could exploit this vulnerability by sending
malicious packets over an established IPsec connection. A successful
exploit could cause the device to crash, forcing it to reload.
Important: Successful exploitation of this vulnerability would not
cause a compromise of any encrypted data. Note: This vulnerability
affects only Cisco ASA Software Release 9.16.1 and Cisco FTD Software
Release 7.0.0.

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-asa-ftd-ipsec-dos-TFKQbgWC
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?0b3df468");
  script_set_attribute(attribute:"solution", value:
"Refer to the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/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:C/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-2021-1422");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_cwe_id(617);

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/07/16");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/07/16");
  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:9.16.1");
  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:9.16.1" :
        {"versionEndIncluding" : "9.16.1", "versionStartIncluding" : "9.16.1", "family" : "CiscoFirepower"}
};

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