cr8escape: New Vulnerability in CRI-O Container Engine [CVE-2022-0811]
We discussed this vulnerability during Episode 129 on 21 March 2022
Simple container escape compared to several we’ve covered in the past, the sysctls
passed into the pinns
utility are delimited by a +
which can be maliciously included in a value to inject otherwise blocked sysctls
. There is some minimal validation on the sysctls
being passed in to ensure the keys don’t match any sensitive keys, however an attacker can set a value to +sensitive.key=othervalue
to smuggle in a blocked option.
Smuggling in a kernel.core_pattern
could be used to execute an arbitrary file as root on the host to handle a crash dump. This would require a fairly privileged attacker who is able to deploy pods but may not have underlying access to the host system. It could also be useful as part of a chain.