Denial of service in Cisco IOS XE

1) Improper Check for Unusual or Exceptional Conditions

EUVDB-ID: #VU51769

Risk: Medium

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-2021-1446

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 that occurs when an affected device inspects certain DNS packets. A remote attacker can send specially crafted DNS packets and cause denial of service condition.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Cisco IOS XE: 16.9.5

Cisco ASR 1000 Series Aggregation Services Routers: All versions

Cloud Services Router 1000V Series: All versions

4000 Series Integrated Services Routers: All versions

Cisco 1000 Series Integrated Services Routers: All versions

External links

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-alg-dos-hbBS7SZE

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.