Symlink Attack in kubectl cp in k8s.io/kubernetes
Symlink Attack in kubectl cp in k8s.io/kubernetes
02 / AFFECTED SOFTWARE
Affected packages
47 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
Symlink Attack in kubectl cp in k8s.io/kubernetes
The kubectl cp command allows copying files between containers and the user machine. To copy files from a container, Kubernetes creates a tar inside the container, copies it over the network, and kubectl unpacks it on the user’s machine. If the tar binary in the container is malicious, it could run any code and output unexpected, malicious results. An attacker could use this to write files to any path on the user’s machine when kubectl cp is called, limited only by the system permissions of the local user. The untar function can both create and follow symbolic links. The issue is resolved in kubectl v1.11.9, v1.12.7, v1.13.5, and v1.14.0.
The kubectl cp command allows copying files between containers and the user machine. To copy files from a container, Kubernetes creates a tar inside the container, copies it over the network, and kubectl unpacks it on the user’s machine. If the tar binary in the container is malicious, it could run any code and output unexpected, malicious results. An attacker could use this to write files to any path on the user’s machine when kubectl cp is called, limited only by the system permissions of the local user. The untar function can both create and follow symbolic links. The issue is resolved in kubectl v1.11.9, v1.12.7, v1.13.5, and v1.14.0.
05 / REFERENCES
Further evidence
- http://www.openwall.com/lists/oss-security/2019/06/21/1
- http://www.openwall.com/lists/oss-security/2019/08/05/5
- https://access.redhat.com/errata/RHBA-2019:0619
- https://access.redhat.com/errata/RHBA-2019:0620
- https://access.redhat.com/errata/RHBA-2019:0636
- https://github.com/advisories/GHSA-34jx-wx69-9x8v
- https://github.com/kubernetes/kubernetes/commit/47063891dd782835170f500a83f37cc98c3c1013
- https://github.com/kubernetes/kubernetes/pull/75037
- https://lists.fedoraproject.org/archives/list/[email protected]/message/BPV2RE5RMOGUVP5WJMXKQJZUBBLAFZPZ
- https://lists.fedoraproject.org/archives/list/[email protected]/message/QZB7E3DOZ5WDG46XAIU6K32CXHXPXB2F
- https://www.twistlock.com/labs-blog/disclosing-directory-traversal-vulnerability-kubernetes-copy-cve-2019-1002101
- http://www.securityfocus.com/bid/107652
- https://nvd.nist.gov/vuln/detail/CVE-2019-1002101
- https://access.redhat.com/security/cve/cve-2019-1002101
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BPV2RE5RMOGUVP5WJMXKQJZUBBLAFZPZ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QZB7E3DOZ5WDG46XAIU6K32CXHXPXB2F/
- https://www.twistlock.com/labs-blog/disclosing-directory-traversal-vulnerability-kubernetes-copy-cve-2019-1002101/