Apache ZooKeeper: Unauthenticated persistent denial of service via unvalidated quota-node data and paths crashing the transaction-apply thread

Summary

Improper handling of exceptional conditions in the quota subsystem of Apache ZooKeeper allows an attacker able to write under the /zookeeper/quota subtree — unauthenticated on default deployments, where that subtree is world-writable — to crash the server's critical request-processing thread and render the on-disk data directory permanently unbootable. This issue affects Apache ZooKeeper up to and including 3.9.6. Users are recommended to upgrade to version 3.8.8 or 3.9.7, which fixes the issue.

Remediation

1. Inventory every Apache Software Foundation Apache ZooKeeper deployment, including staging.
2. No fixed version appears in the public sources yet. Check the references below and the vendor directly.

References

• Advisoryhttps://lists.apache.org/thread.html/09pgg7rcpzz44noxgtvpzstwt8fmvsb0