Cisco ASA Stack-based Buffer Overflow (CVE-2021-34704)

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

include('compat.inc');

if (description)
{
  script_id(506184);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/07");

  script_cve_id("CVE-2021-34704");

  script_name(english:"Cisco ASA Stack-based Buffer Overflow (CVE-2021-34704)");

  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 web services interface of Cisco Adaptive
Security Appliance (ASA) Software and Cisco Firepower Threat Defense
(FTD) Software could allow an unauthenticated, remote attacker to
trigger a denial of service (DoS) condition. This vulnerability is due
to improper input validation when parsing HTTPS requests. An attacker
could exploit this vulnerability by sending a malicious HTTPS request
to an affected device. A successful exploit could allow the attacker
to cause the device to reload, resulting in a DoS condition.

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-asafdt-webvpn-dos-KSqJAKPA
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?47a2b253");
  script_set_attribute(attribute:"solution", value:
"Refer to the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/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: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-2021-34704");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_cwe_id(121, 787);

  script_set_attribute(attribute:"vuln_publication_date", value:"2022/01/11");
  script_set_attribute(attribute:"patch_publication_date", value:"2022/01/11");
  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:9.15" :
        {"versionEndExcluding" : "9.15.1.17", "versionStartIncluding" : "9.15", "family" : "CiscoFirepower"},
    "cpe:/o:cisco:adaptive_security_appliance_software:9.16" :
        {"versionEndExcluding" : "9.16.2", "versionStartIncluding" : "9.16", "family" : "CiscoFirepower"}
};

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