Vulnerability CVE-2020-8562

Vulnerability Name:

CVE-2020-8562 (CCN-201273)

Assigned:

2020-02-03

Published:

2021-05-04

Updated:

2022-03-29

Summary:

As mitigations to a report from 2019 and CVE-2020-8555, Kubernetes attempts to prevent proxied connections from accessing link-local or localhost networks when making user-driven connections to Services, Pods, Nodes, or StorageClass service providers. As part of this mitigation Kubernetes does a DNS name resolution check and validates that response IPs are not in the link-local (169.254.0.0/16) or localhost (127.0.0.0/8) range. Kubernetes then performs a second DNS resolution without validation for the actual connection. If a non-standard DNS server returns different non-cached responses, a user may be able to bypass the proxy IP restriction and access private networks on the control plane.

CVSS v3 Severity:

3.1 Low (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N)
2.8 Low (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N/E:U/RL:U/RC:R)

Exploitability Metrics:	Attack Vector (AV): Network Attack Complexity (AC): High Privileges Required (PR): Low User Interaction (UI): None
Scope:	Scope (S): Unchanged
Impact Metrics:	Confidentiality (C): Low Integrity (I): None Availibility (A): None

2.2 Low (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N)
2.0 Low (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N/E:U/RL:U/RC:R)

Exploitability Metrics:	Attack Vector (AV): Network Attack Complexity (AC): High Privileges Required (PR): High User Interaction (UI): None
Scope:	Scope (S): Unchanged
Impact Metrics:	Confidentiality (C): Low Integrity (I): None Availibility (A): None

CVSS v2 Severity:

3.5 Low (CVSS v2 Vector: AV:N/AC:M/Au:S/C:P/I:N/A:N)

Exploitability Metrics:	Access Vector (AV): Network Access Complexity (AC): Medium Authentication (Au): Single_Instance
Impact Metrics:	Confidentiality (C): Partial Integrity (I): None Availibility (A): None

2.1 Low (CCN CVSS v2 Vector: AV:N/AC:H/Au:S/C:P/I:N/A:N)

Exploitability Metrics:	Access Vector (AV): Network Access Complexity (AC): High Athentication (Au): Single_Instance
Impact Metrics:	Confidentiality (C): Partial Integrity (I): None Availibility (A): None