Authorization Bypass Through User-Controlled Key vulnerability in Apache ZooKeeper. If SASL Quorum Peer authentication is enabled in ZooKeeper (quorum.auth.enableSasl=true), the authorization is done by verifying that the instance part in SASL authentication ID is listed in zoo.cfg server list. The instance part in SASL auth ID is optional and if its missing, like eve@EXAMPLE.COM, the authorization check will be skipped. As a result an arbitrary endpoint could join the cluster and begin propagating counterfeit changes to the leader, essentially giving it complete read-write access to the data tree. Quorum Peer authentication is not enabled by default.
Users are recommended to upgrade to version 3.9.1, 3.8.3, 3.7.2, which fixes the issue.
Alternately ensure the ensemble election/quorum communication is protected by a firewall as this will mitigate the issue.
See the documentation for more details on correct cluster administration.
The system’s authorization functionality does not prevent one user from gaining access to another user’s data or record by modifying the key value identifying the data.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Zookeeper | Apache | * | 3.7.2 (excluding) |
| Zookeeper | Apache | 3.8.0 (including) | 3.8.3 (excluding) |
| Zookeeper | Apache | 3.9.0 (including) | 3.9.0 (including) |
| AMQ Broker 7.10.6 | RedHat | zookeeper | * |
| Red Hat AMQ Broker 7 | RedHat | zookeeper | * |
| Red Hat AMQ Broker 7.11.6 | RedHat | zookeeper | * |
| Red Hat AMQ Streams 2.6.0 | RedHat | zookeeper | * |
| Zookeeper | Ubuntu | bionic | * |
| Zookeeper | Ubuntu | esm-apps/bionic | * |
| Zookeeper | Ubuntu | focal | * |
| Zookeeper | Ubuntu | jammy | * |
| Zookeeper | Ubuntu | lunar | * |
| Zookeeper | Ubuntu | mantic | * |
| Zookeeper | Ubuntu | trusty | * |
| Zookeeper | Ubuntu | upstream | * |
| Zookeeper | Ubuntu | xenial | * |
Retrieval of a user record occurs in the system based on some key value that is under user control. The key would typically identify a user-related record stored in the system and would be used to lookup that record for presentation to the user. It is likely that an attacker would have to be an authenticated user in the system. However, the authorization process would not properly check the data access operation to ensure that the authenticated user performing the operation has sufficient entitlements to perform the requested data access, hence bypassing any other authorization checks present in the system. For example, attackers can look at places where user specific data is retrieved (e.g. search screens) and determine whether the key for the item being looked up is controllable externally. The key may be a hidden field in the HTML form field, might be passed as a URL parameter or as an unencrypted cookie variable, then in each of these cases it will be possible to tamper with the key value. One manifestation of this weakness is when a system uses sequential or otherwise easily-guessable session IDs that would allow one user to easily switch to another user’s session and read/modify their data.