Cisco Email Security Appliance DNS Verification DoS (cisco-sa-esa-dos-MxZvGtgU)

high Nessus Plugin ID 166391


The remote device is missing a vendor-supplied security patch.


According to its self-reported version, Cisco Email Security Appliance is affected by a vulnerability in the DNS-based Authentication of Named Entities (DANE) email verification component that allows an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient error handling in DNS name resolution by the affected software. An attacker could exploit this vulnerability by sending specially formatted email messages that are processed by an affected device. A successful exploit could allow the attacker to cause the device to become unreachable from management interfaces or to process additional email messages for a period of time until the device recovers, resulting in a DoS condition. Continued attacks could cause the device to become completely unavailable, resulting in a persistent DoS condition.

Please see the included Cisco BIDs and Cisco Security Advisory for more information.


Upgrade to the relevant fixed version referenced in Cisco bug ID CSCvy63674

See Also

Plugin Details

Severity: High

ID: 166391

File Name: cisco-sa-esa-dos-MxZvGtgU.nasl

Version: 1.4

Type: combined

Family: CISCO

Published: 10/21/2022

Updated: 10/24/2022

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information


Risk Factor: Low

Score: 3.6


Risk Factor: High

Base Score: 7.1

Temporal Score: 5.3

Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2022-20653


Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:cisco:email_security_appliance_firmware, cpe:/a:cisco:email_security_appliance

Required KB Items: Settings/ParanoidReport, Host/AsyncOS/Cisco Email Security Appliance/Version

Exploit Ease: No known exploits are available

Patch Publication Date: 2/16/2022

Vulnerability Publication Date: 2/16/2022

Reference Information

CVE: CVE-2022-20653

CWE: 399

CISCO-SA: cisco-sa-esa-dos-MxZvGtgU