8.6
HIGH
CVE-2020-3421
Cisco IOS XE Zone-Based Firewall Layer 4 Packet Processing Denial of Service
Description

Multiple vulnerabilities in the Zone-Based Firewall feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause the device to reload or stop forwarding traffic through the firewall. The vulnerabilities are due to incomplete handling of Layer 4 packets through the device. An attacker could exploit these vulnerabilities by sending a certain sequence of traffic patterns through the device. A successful exploit could allow the attacker to cause the device to reload or stop forwarding traffic through the firewall, resulting in a denial of service. For more information about these vulnerabilities, see the Details section of this advisory.

INFO

Published Date :

Sept. 24, 2020, 6:15 p.m.

Last Modified :

Nov. 21, 2024, 5:31 a.m.

Remotely Exploitable :

Yes !

Impact Score :

4.0

Exploitability Score :

3.9
Affected Products

The following products are affected by CVE-2020-3421 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Cisco ios_xe
2 Cisco asr_1002-x
3 Cisco asr_1004
4 Cisco asr_1006
5 Cisco asr_1013
6 Cisco 1100_integrated_services_router
7 Cisco 1101_integrated_services_router
8 Cisco 1109_integrated_services_router
9 Cisco 111x_integrated_services_router
10 Cisco 1120_integrated_services_router
11 Cisco 1160_integrated_services_router
12 Cisco 4221_integrated_services_router
13 Cisco asr_1001-hx
14 Cisco asr_1001-x
15 Cisco asr_1002-hx
16 Cisco asr_1006-x
17 Cisco asr_1009-x
18 Cisco 1111x_integrated_services_router
19 Cisco 4321_integrated_services_router
20 Cisco 4331_integrated_services_router
21 Cisco 4351_integrated_services_router
22 Cisco 4431_integrated_services_router
23 Cisco 4461_integrated_services_router
24 Cisco csr_1000v
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2020-3421.

URL Resource
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-zbfw-94ckG4G Vendor Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-zbfw-94ckG4G Vendor Advisory

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2020-3421 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2020-3421 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-zbfw-94ckG4G
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Nov. 07, 2023

    Action Type Old Value New Value
    Removed CVSS V3 Cisco Systems, Inc. AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
    Added CVSS V3.1 Cisco Systems, Inc. AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_4321:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:4321_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_4351:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:4351_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_4431:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:4431_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_4461:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:4461_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_1100:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:1100_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_1101:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:1101_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_111x:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:111x_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_1111x:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:1111x_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_1120:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:1120_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_1160:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:1160_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_1109:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:1109_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_4221:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:4221_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_4331:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:4331_integrated_services_router:-:*:*:*:*:*:*:*
  • Initial Analysis by [email protected]

    Oct. 09, 2020

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:M/Au:N/C:N/I:N/A:C)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    Changed Reference Type https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-zbfw-94ckG4G No Types Assigned https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-zbfw-94ckG4G Vendor Advisory
    Added CWE NIST CWE-754
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ios_xe:16.9.3:*:*:*:*:*:*:* OR cpe:2.3:h:cisco:asr_1001-hx:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1001-x:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1002-hx:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1002-x:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1004:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1006:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1006-x:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1009-x:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1013:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_4221:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_4321:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_4331:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_4351:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_4431:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_4461:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ios_xe:17.2:*:*:*:*:*:*:* OR cpe:2.3:h:cisco:asr_1001-hx:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1001-x:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1002-hx:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1002-x:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1004:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1006:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1006-x:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1009-x:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_1013:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:csr_1000v:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_1100:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_1101:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_1109:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_1111x:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_111x:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_1120:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_1160:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_4221:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_4331:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_4431:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:isr_4461:-:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Sep. 24, 2020

    Action Type Old Value New Value
    Changed Description Multiple vulnerabilities in the Zone-Based Firewall feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause the device to reload or stop forwarding traffic through the firewall. The vulnerabilities are due to incomplete handling of Layer 4 packets through the device. An attacker could exploit these vulnerabilities by sending a certain sequence of traffic patterns through the device. A successful exploit could allow the attacker to cause the device to reload or stop forwarding traffic through the firewall, resulting in a denial of service. For more information about these vulnerabilities, see the Details section of this advisory. Multiple vulnerabilities in the Zone-Based Firewall feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause the device to reload or stop forwarding traffic through the firewall. The vulnerabilities are due to incomplete handling of Layer 4 packets through the device. An attacker could exploit these vulnerabilities by sending a certain sequence of traffic patterns through the device. A successful exploit could allow the attacker to cause the device to reload or stop forwarding traffic through the firewall, resulting in a denial of service. For more information about these vulnerabilities, see the Details section of this advisory.
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2020-3421 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2020-3421 weaknesses.

Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.16 }} 0.02%

score

0.51298

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability