CVE-2020-26278
Published: 20 January 2021
Summary
CVE-2020-26278 is a medium-severity Execution with Unnecessary Privileges (CWE-250) vulnerability in Weave Weave. Its CVSS base score is 5.8 (Medium).
Operationally, ranked at the 36.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2020-18852
Vulnerability details
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…
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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.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Policy promotes least privilege by defining necessary privileges and management commitment to them.
Supervision detects and allows removal of unnecessary privileges that enable execution with excess rights.
Reviewing accounts for compliance, disabling/removing unneeded accounts, and aligning with termination processes prevents execution with unnecessary privileges.
Separation of duties prevents any single user from holding all privileges needed to complete a critical task, directly reducing execution with unnecessary privileges.
Directly prevents execution with more privileges than needed for assigned tasks.
Role-based training on least privilege principles reduces the chance personnel assign or retain unnecessary privileges.
Analysis of audit records can identify execution with unnecessary privileges through unusual activity patterns.
Automatic termination after a defined period eliminates unnecessary privileges from persistent connections.