Security Bulletins

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Description

In vulnerable versions of Calico (v3.27.2 and below), Calico Enterprise (v3.19.0-1, v3.18.1, v3.17.3 and below), and Calico Cloud (v19.2.0 and below), an attacker who has local access to the Kubernetes node, can escalate their privileges by exploiting a vulnerability in the Calico CNI install binary. The issue arises from an incorrect SUID (Set User ID) bit configuration in the binary, combined with the ability to control the input binary, allowing an attacker to execute an arbitrary binary with elevated privileges.

Severity

CVSSv3.1: Medium (6.7)

Vector: AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

In the rare scenario where an attacker has gained local access to the Kubernetes nodes, the attacker can execute an arbitrary binary with elevated privileges. This requires manipulating Calico install environment variables and replacing the legitimate Calico binary with their own malicious binary.

References

Weakness Enumeration

CWE-269: Improper Privilege Management

Indicators of Impact/Compromise

Review logs for abnormal access patterns to the Kubernetes nodes such as from new or unexpected IPs.

Workaround/Mitigation

Review access control and monitoring for the Kubernetes nodes and increase restrictions to the nodes.

Affected Releases

• Calico OSS
  • v3.27.2 and below
  • v3.26.4 and below
• Calico Enterprise
  • v3.19.0-1.0 and below
  • v3.18.1 and below
  • v3.17.3 and below
• Calico Cloud
  • v19.2.0 and below

Fixed Versions

• Calico OSS
  • v3.28.0 and above
  • v3.27.3 – released April 2, 2024
  • v3.26.5 – to be released
• Calico Enterprise
  • v3.19.0-2.0 and above
  • v3.18.2 – released March 26, 2024
  • v3.17.4 – released March 14, 2024
• Calico Cloud
  • v19.3.0 and above – to be released

Acknowledgment

We would like to thank Christopher Alonso from IBM (Github: @latortuga71) for the discovery and for providing additional details to Tigera SIRT.

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