Authorization Bypass Through User-Controlled Key (CWE-639) in Kibana could lead to cross-tenant data interception. In this context, tenant refers to a user or team sharing the same Kibana deployment, not a separate Elastic Cloud organization or customer. Kibanas Fleet package installation process allowed a user holding delegated Fleet package-management privileges, without direct Elasticsearch administrative privileges, to claim a data stream identifier already in use by another tenant. Because ownership of that identifier was not verified before Fleet applied the uploaded packages generated index and ingest-pipeline settings to already-existing infrastructure, an attacker could redirect an existing tenants data stream through infrastructure under their control. This exposed the affected tenants subsequently ingested data to unauthorized disclosure and modification, and prevented that data from reaching its intended destination. Interception could continue even after the malicious package was removed, requiring separate remediation of the affected infrastructure.
Weakness
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.
Extended Description
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.