CVE-2021-34793

Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Transparent Mode Denial of Service Vulnerability

Severity Score

8.6

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Attend

*SSVC

Descriptions

A vulnerability in the TCP Normalizer of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software operating in transparent mode could allow an unauthenticated, remote attacker to poison MAC address tables, resulting in a denial of service (DoS) vulnerability. This vulnerability is due to incorrect handling of certain TCP segments when the affected device is operating in transparent mode. An attacker could exploit this vulnerability by sending a crafted TCP segment through an affected device. A successful exploit could allow the attacker to poison the MAC address tables in adjacent devices, resulting in network disruption.

Una vulnerabilidad en el Normalizador TCP del software Cisco Adaptive Security Appliance (ASA) y del software Firepower Threat Defense (FTD) que funciona en modo transparente podría permitir a un atacante remoto no autenticado envenenar las tablas de direcciones MAC, lo que provocaría una vulnerabilidad de denegación de servicio (DoS). Esta vulnerabilidad es debido al manejo incorrecto de determinados segmentos TCP cuando el dispositivo afectado está operando en modo transparente. Un atacante podría explotar esta vulnerabilidad mediante el envío de un segmento TCP diseñado mediante un dispositivo afectado. Una explotación con éxito podría permitir al atacante envenenar las tablas de direcciones MAC en los dispositivos adyacentes, resultando en una interrupción de la red

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:Attend

Exploitation

None

Automatable

Yes

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2021-06-15 CVE Reserved
2021-10-27 CVE Published
2024-07-12 EPSS Updated
2024-11-07 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-924: Improper Enforcement of Message Integrity During Transmission in a Communication Channel

CAPEC

References (1)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-dos-JxYWMJyL	2023-11-07

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Cisco Search vendor "Cisco"	Asa 5512-x Firmware Search vendor "Cisco" for product "Asa 5512-x Firmware"	009.008\(004.025\) Search vendor "Cisco" for product "Asa 5512-x Firmware" and version "009.008\(004.025\)"	-	Affected	in	Cisco Search vendor "Cisco"	Asa 5512-x Search vendor "Cisco" for product "Asa 5512-x"	-	-	Safe
Cisco Search vendor "Cisco"	Asa 5505 Firmware Search vendor "Cisco" for product "Asa 5505 Firmware"	009.008\(004.025\) Search vendor "Cisco" for product "Asa 5505 Firmware" and version "009.008\(004.025\)"	-	Affected	in	Cisco Search vendor "Cisco"	Asa 5505 Search vendor "Cisco" for product "Asa 5505"	-	-	Safe
Cisco Search vendor "Cisco"	Asa 5515-x Firmware Search vendor "Cisco" for product "Asa 5515-x Firmware"	009.008\(004.025\) Search vendor "Cisco" for product "Asa 5515-x Firmware" and version "009.008\(004.025\)"	-	Affected	in	Cisco Search vendor "Cisco"	Asa 5515-x Search vendor "Cisco" for product "Asa 5515-x"	-	-	Safe
Cisco Search vendor "Cisco"	Asa 5525-x Firmware Search vendor "Cisco" for product "Asa 5525-x Firmware"	009.008\(004.025\) Search vendor "Cisco" for product "Asa 5525-x Firmware" and version "009.008\(004.025\)"	-	Affected	in	Cisco Search vendor "Cisco"	Asa 5525-x Search vendor "Cisco" for product "Asa 5525-x"	-	-	Safe
Cisco Search vendor "Cisco"	Asa 5545-x Firmware Search vendor "Cisco" for product "Asa 5545-x Firmware"	009.008\(004.025\) Search vendor "Cisco" for product "Asa 5545-x Firmware" and version "009.008\(004.025\)"	-	Affected	in	Cisco Search vendor "Cisco"	Asa 5545-x Search vendor "Cisco" for product "Asa 5545-x"	-	-	Safe
Cisco Search vendor "Cisco"	Asa 5555-x Firmware Search vendor "Cisco" for product "Asa 5555-x Firmware"	009.008\(004.025\) Search vendor "Cisco" for product "Asa 5555-x Firmware" and version "009.008\(004.025\)"	-	Affected	in	Cisco Search vendor "Cisco"	Asa 5555-x Search vendor "Cisco" for product "Asa 5555-x"	-	-	Safe
Cisco Search vendor "Cisco"	Asa 5580 Firmware Search vendor "Cisco" for product "Asa 5580 Firmware"	009.008\(004.025\) Search vendor "Cisco" for product "Asa 5580 Firmware" and version "009.008\(004.025\)"	-	Affected	in	Cisco Search vendor "Cisco"	Asa 5580 Search vendor "Cisco" for product "Asa 5580"	-	-	Safe
Cisco Search vendor "Cisco"	Asa 5585-x Firmware Search vendor "Cisco" for product "Asa 5585-x Firmware"	009.008\(004.025\) Search vendor "Cisco" for product "Asa 5585-x Firmware" and version "009.008\(004.025\)"	-	Affected	in	Cisco Search vendor "Cisco"	Asa 5585-x Search vendor "Cisco" for product "Asa 5585-x"	-	-	Safe
Cisco Search vendor "Cisco"		Adaptive Security Appliance Search vendor "Cisco" for product "Adaptive Security Appliance"				< 9.8.4.40 Search vendor "Cisco" for product "Adaptive Security Appliance" and version " < 9.8.4.40"		-		Affected
Cisco Search vendor "Cisco"		Firepower Threat Defense Search vendor "Cisco" for product "Firepower Threat Defense"				< 6.4.0.13 Search vendor "Cisco" for product "Firepower Threat Defense" and version " < 6.4.0.13"		-		Affected
Cisco Search vendor "Cisco"		Firepower Threat Defense Search vendor "Cisco" for product "Firepower Threat Defense"				>= 6.5.0 < 6.6.5 Search vendor "Cisco" for product "Firepower Threat Defense" and version " >= 6.5.0 < 6.6.5"		-		Affected
Cisco Search vendor "Cisco"		Firepower Threat Defense Search vendor "Cisco" for product "Firepower Threat Defense"				>= 6.7.0 < 6.7.0.3 Search vendor "Cisco" for product "Firepower Threat Defense" and version " >= 6.7.0 < 6.7.0.3"		-		Affected
Cisco Search vendor "Cisco"		Adaptive Security Appliance Software Search vendor "Cisco" for product "Adaptive Security Appliance Software"				>= 9.9.0 < 9.12.4.29 Search vendor "Cisco" for product "Adaptive Security Appliance Software" and version " >= 9.9.0 < 9.12.4.29"		-		Affected
Cisco Search vendor "Cisco"		Adaptive Security Appliance Software Search vendor "Cisco" for product "Adaptive Security Appliance Software"				>= 9.13.0 < 9.14.3.9 Search vendor "Cisco" for product "Adaptive Security Appliance Software" and version " >= 9.13.0 < 9.14.3.9"		-		Affected
Cisco Search vendor "Cisco"		Adaptive Security Appliance Software Search vendor "Cisco" for product "Adaptive Security Appliance Software"				>= 9.15.0 < 9.15.1.17 Search vendor "Cisco" for product "Adaptive Security Appliance Software" and version " >= 9.15.0 < 9.15.1.17"		-		Affected
Cisco Search vendor "Cisco"		Adaptive Security Appliance Software Search vendor "Cisco" for product "Adaptive Security Appliance Software"				>= 9.16.0 < 9.16.2.3 Search vendor "Cisco" for product "Adaptive Security Appliance Software" and version " >= 9.16.0 < 9.16.2.3"		-		Affected