Headline
CVE-2023-23939: Azure/setup-kubectl: Escalation of privilege vulnerability for v3 and lower
Azure/setup-kubectl is a GitHub Action for installing Kubectl. This vulnerability only impacts versions before version 3. An insecure temporary creation of a file allows other actors on the Actions runner to replace the Kubectl binary created by this action because it is world writable. This Kubectl tool installer runs fs.chmodSync(kubectlPath, 777) to set permissions on the Kubectl binary, however, this allows any local user to replace the Kubectl binary. This allows privilege escalation to the user that can also run kubectl, most likely root. This attack is only possible if an attacker somehow breached the GitHub actions runner or if a user is utilizing an Action that maliciously executes this attack. This has been fixed and released in all versions v3 and later. 775 permissions are used instead. Users are advised to upgrade. There are no known workarounds for this issue.
Impact
This vulnerability only impacts versions v2 and lower. An insecure temporary creation of a file allows other actors on the Actions runner to replace the Kubectl binary created by this action because it is world writable. This Kubectl tool installer runs fs.chmodSync(kubectlPath, 777) to set permissions on the Kubectl binary, however, this allows any local user to replace the Kubectl binary. This allows privilege escalation to the user that can also run kubectl, most likely root. This attack is only possible if an attacker somehow breached the GitHub actions runner or if a user is utilizing an Action that maliciously executes this attack.
No impacted customers have been reported.
Patches
This has been fixed and released in all versions v3 and later. 755 permissions are used instead.
Workarounds
If users absolutely cannot upgrade to v3 or higher than they should be extra diligent of the other GitHub actions they are using in a workflow and ensure that their GitHub actions runner is secure.
Related news
### Impact This vulnerability only impacts versions `v2` and lower. An insecure temporary creation of a file allows other actors on the Actions runner to replace the Kubectl binary created by this action because it is world writable. This Kubectl tool installer runs `fs.chmodSync(kubectlPath, 777)` to set permissions on the Kubectl binary, however, this allows any local user to replace the Kubectl binary. This allows privilege escalation to the user that can also run kubectl, most likely root. This attack is only possible if an attacker somehow breached the GitHub actions runner or if a user is utilizing an Action that maliciously executes this attack. No impacted customers have been reported. ### Patches This has been fixed and released in all versions `v3` and later. 755 permissions are used instead. ### Workarounds If users absolutely cannot upgrade to `v3` or higher than they should be extra diligent of the other GitHub actions they are using in a workflow and ensure that the...