containerd CRI plugin: Host memory exhaustion through ExecSync

Impact

A bug was found in containerd’s CRI implementation where programs inside a container can cause the containerd daemon to consume memory without bound during invocation of the ExecSync API. This can cause containerd to consume all available memory on the computer, denying service to other legitimate workloads. Kubernetes and crictl can both be configured to use containerd’s CRI implementation; ExecSync may be used when running probes or when executing processes via an “exec” facility.

Patches

This bug has been fixed in containerd 1.6.6 and 1.5.13. Users should update to these versions to resolve the issue.

Workarounds

Ensure that only trusted images and commands are used.

References

• Similar fix in cri-o’s CRI implementation https://github.com/cri-o/cri-o/security/advisories/GHSA-fcm2-6c3h-pg6j

Credits

The containerd project would like to thank David Korczynski and Adam Korczynski of ADA Logics for responsibly disclosing this issue in accordance with the containerd security policy during a security audit sponsored by CNCF and facilitated by OSTIF.

For more information

If you have any questions or comments about this advisory:

• Open an issue in containerd
• Email us at [email protected]