CVE-2020-27833

A Zip Slip vulnerability was found in the oc binary in openshift-clients where an arbitrary file write is achieved by using a specially crafted raw container image (.tar file) which contains symbolic links. The vulnerability is limited to the command oc image extract. If a symbolic link is first created pointing within the tarball, this allows further symbolic links to bypass the existing path check. This flaw allows the tarball to create links outside the tarball’s parent directory, allowing for executables or configuration files to be overwritten, resulting in arbitrary code execution. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

Mitigation

The option --only-files=true can be specified to ensure that only files and directories from the image are extracted and symbolic links are ignored. While this means that if a image does implement malicious symbolic links, no links will be created outside the parent tarball. However, this does mean that if legitimate symbolic links are specific within the image these will also not be created.