Symlink Attack Affecting k8s.io/kubernetes/pkg/kubelet package, versions >=1.3.0 <1.7.14 >=1.8.0 <1.8.9 >=1.9.0 <1.9.4


Severity

Recommended
0.0
medium
0
10

CVSS assessment made by Snyk's Security Team

    Threat Intelligence

    EPSS
    0.04% (14th percentile)

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  • Snyk ID SNYK-GOLANG-K8SIOKUBERNETESPKGKUBELET-2826201
  • published 17 May 2022
  • disclosed 17 May 2022
  • credit Joel Smith of Red Hat

How to fix?

Upgrade k8s.io/kubernetes/pkg/kubelet to version 1.7.14, 1.8.9, 1.9.4 or higher.

Overview

k8s.io/kubernetes/pkg/kubelet is a package that contains the libraries that drive the Kubelet binary. The kubelet is responsible for node level pod management. It runs on each worker in the cluster.

Affected versions of this package are vulnerable to Symlink Attack due to a symlink race. Every synchronization iteration, the Atomic Writer is looking for files that shouldn't be in a volume, and when it finds it is added to a list. When the search is done it deletes the files in the list. Because the deletion doesn't occur during the finding of the file, a malicious container can set up conditions to change the file selected for deletion with a symlink leading to a different file, which will be deleted.

CVSS Scores

version 3.1
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Snyk

Recommended
6.1 medium
  • Attack Vector (AV)
    Local
  • Attack Complexity (AC)
    Low
  • Privileges Required (PR)
    Low
  • User Interaction (UI)
    None
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    None
  • Integrity (I)
    Low
  • Availability (A)
    High