Denial of service in Cisco IOS XE Software

1) Improper Check for Unusual or Exceptional Conditions

EUVDB-ID: #VU67736

Risk: High

CVSSv3.1: 7.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2022-20837

CWE-ID: CWE-754 - Improper Check for Unusual or Exceptional Conditions

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a logic error in the DNS application layer gateway (ALG) functionality that is used by Network Address Translation (NAT). A remote attacker can send specially crafted DNS packets and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Cisco IOS XE: 17.3.4a

ASR 1000 Series Embedded Services Processors model ESP 100-X: All versions

ASR 1000 Series Embedded Services Processors model ESP 200-X: All versions

Catalyst 8500 Series Edge Platforms model C8500-12X4QC: All versions

Catalyst 8500 Series Edge Platforms model C8500-12X: All versions

External links

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-alg-dos-KU9Z8kFX

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.