CVE-2020-26278 Information

Description

Weave Net is open source software which creates a virtual network that connects Docker containers across multiple hosts and enables their automatic discovery. Weave Net before version 2.8.0 has a vulnerability in which can allow an attacker to take over any host in the cluster. Weave Net is supplied with a manifest that runs pods on every node in a Kubernetes cluster which are responsible for managing network connections for all other pods in the cluster. This requires a lot of power over the host and the manifest sets privileged: true which gives it that power. It also set hostPID: true which gave it the ability to access all other processes on the host and write anywhere in the root filesystem of the host. This setting was not necessary and is being removed. You are only vulnerable if you have an additional vulnerability (e.g. a bug in Kubernetes) or misconfiguration that allows an attacker to run code inside the Weave Net pod No such bug is known at the time of release and there are no known instances of this being exploited. Weave Net 2.8.0 removes the hostPID setting and moves CNI plugin install to an init container. Users who do not update to 2.8.0 can edit the hostPID line in their existing DaemonSet manifest to say false instead of true arrange some other way to install CNI plugins (e.g. Ansible) and remove those mounts from the DaemonSet manifest.

CVSS Vector

CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Reference

https://github.com/weaveworks/weave/commit/a0ac81b3b4cae6d0dcaf3732fd91cedefc89f720 https://github.com/weaveworks/weave/security/advisories/GHSA-pg3p-v8c6-c6h3 https://github.com/weaveworks/weave/blob/master/CHANGELOG.md#release-280 https://github.com/weaveworks/weave/pull/3876

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

CHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

8.0