QID 317235

Date Published: 2022-10-18

QID 317235: Cisco Internetwork Operating System (IOS) XE Software Domain Name System (DNS) NAT Protocol Application Layer Gateway Denial of Service (DoS) Vulnerability (cisco-sa-alg-dos-KU9Z8kFX)

A vulnerability in the DNS application layer gateway (ALG) functionality that is used by Network Address Translation (NAT) in Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload.

Affected Products
This vulnerability affects the following Cisco devices if they are running a vulnerable release of Cisco IOS XE Software that is configured for NAT operation and has the DNS ALG for TCP feature enabled. The DNS ALG feature is enabled as soon as NAT is configured on the device.

ASR 1000 Series Embedded Services Processors models ESP 100-X and ESP 200-X
Catalyst 8500 Series Edge Platforms models C8500-12X4QC and C8500-12X

QID Detection Logic (Authenticated):
The check matches Cisco IOS XE version retrieved via Unix Auth using "show version" command.
QID Detection Logic (Unauthenticated):
The check matches Cisco IOS XE version retrieved via SNMP or TCP/IP Fingerprint or NTP or Telnet.

A successful exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition on the affected device.

  • CVSS V3 rated as Critical - 8.6 severity.
  • CVSS V2 rated as High - 7.1 severity.
    • Solution

    Customers are advised to refer to cisco-sa-alg-dos-KU9Z8kFX for more information.

    Vendor References

    CVEs related to QID 317235

    CVE-2022-20837 |
    Software Advisories
    Advisory ID Software Component Link
    cisco-sa-alg-dos-KU9Z8kFX URL Logo tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-alg-dos-KU9Z8kFX
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