Cisco IOS XE Zone-Based Firewall unusual condition

Summaryinfo

A vulnerability was found in Cisco IOS XE. It has been rated as problematic. Affected is an unknown function of the component Zone-Based Firewall. This manipulation causes unusual condition. This vulnerability is registered as CVE-2020-3421. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as problematic was found in Cisco IOS XE (Router Operating System) (version unknown). Affected by this vulnerability is an unknown function of the component Zone-Based Firewall. The manipulation with an unknown input leads to a unusual condition vulnerability. The CWE definition for the vulnerability is CWE-754. The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product. As an impact it is known to affect availability. The summary by CVE is:

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.

The weakness was published 09/24/2020 as cisco-sa-zbfw-94ckG4G as confirmed advisory (Website). It is possible to read the advisory at tools.cisco.com. This vulnerability is known as CVE-2020-3421 since 12/12/2019. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/25/2020).

Upgrading eliminates this vulnerability.

Similar entry is available at VDB-161888. Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Router Operating System

Vendor

• Cisco

Name

• IOS XE

License

• commercial

Website

• Vendor: https://www.cisco.com/

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