Oauth tokens are not encrypted when encryption of data at rest is enabled. An attacker with access to a backup could obtain oauth tokens and use them to log into the cluster as any user who had logged into the cluster via the webui.
Acknowledgments: Name: Stefan Schimanski (Red Hat)
Mitigation: If you have made a vulnerable backup public you can revoke leaked OAuth tokens by deleting them with the OpenShift API.
To be more precise, this affects OAuthAccessToken and OAuthAuthorizeToken in the auth.openshift.io API group.
Statement: This issue only affects OpenShift Container Platform when the 'encryption at rest' feature enabled, see https://access.redhat.com/documentation/en-us/openshift_container_platform/4.3/html/authentication/encrypting-etcd. When backing up the encrypted data the keys should be stored separately to the data, making backups the most likely target of this attack.
What is the target release to fix this vulnerability?
If the entire backup disk is encrypted with something like AWS KMS that should cover this problem right? In that the entire backup would be encrypted and unusable due to KMS if it were leaked somewhere.
Indeed, encrypting the entire backup is a good mitigation for this vulnerability. This has been fixed in the OCP 4.6 GA release. I'll update the metadata so the CVE page correctly links to that Errata.
Upstream Commit: https://github.com/openshift/oauth-server/pull/50/commits/ca59bc6db7bbc21b1e3cd8f55c71b1c5ec282515