Vulnerability Name:

CVE-2022-20837 (CCN-237415)

Assigned:2021-11-02
Published:2022-09-28
Updated:2022-10-13
Summary: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. This vulnerability is due to a logic error that occurs when an affected device inspects certain TCP DNS packets. An attacker could exploit this vulnerability by sending crafted DNS packets through the affected device that is performing NAT for DNS packets. 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.
Note: This vulnerability can be exploited only by sending IPv4 TCP packets through an affected device. This vulnerability cannot be exploited by sending IPv6 traffic.
CVSS v3 Severity:8.6 High (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H)
7.5 High (Temporal CVSS v3.1 Vector: 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)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Changed
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
8.6 High (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H)
7.5 High (CCN Temporal CVSS v3.1 Vector: 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)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Changed
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
CVSS v2 Severity:7.8 High (CCN CVSS v2 Vector: AV:N/AC:L/Au:N/C:N/I:N/A:C)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Athentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Complete
Vulnerability Type:CWE-754
Vulnerability Consequences:Denial of Service
References:Source: MITRE
Type: CNA
CVE-2022-20837

Source: XF
Type: UNKNOWN
cisco-iosxe-cve202220837-dos(237415)

Source: CCN
Type: Cisco Security Advisory cisco-sa-alg-dos-KU9Z8kFX
Cisco IOS XE Software DNS NAT Protocol Application Layer Gateway Denial of Service Vulnerability

Source: CISCO
Type: Vendor Advisory
20220928 Cisco IOS XE Software DNS NAT Protocol Application Layer Gateway Denial of Service Vulnerability

Vulnerable Configuration:Configuration 1:
  • cpe:/o:cisco:ios_xe:-:*:*:*:*:*:*:*
  • AND
  • cpe:/h:cisco:catalyst_8500:-:*:*:*:*:*:*:*
  • OR cpe:/h:cisco:catalyst_8500-4qc:-:*:*:*:*:*:*:*
  • OR cpe:/h:cisco:asr_1000-esp200-x:-:*:*:*:*:*:*:*
  • OR cpe:/h:cisco:asr_1000-esp100-x:-:*:*:*:*:*:*:*

    • Configuration CCN 1:
  • cpe:/o:cisco:ios_xe_software:*:*:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    BACK
    cisco ios xe -
    cisco catalyst 8500 -
    cisco catalyst 8500-4qc -
    cisco asr 1000-esp200-x -
    cisco asr 1000-esp100-x -
    cisco ios xe software *