AI analysis
Apache NiFi 1.5.0 through 2.11.0 authorize the REST API methods that replace a Process Group's flow (flow replacement, versioned flow update, and rebase) using only read/write privileges on the Process Group itself, omitting the checks on encapsulated components and referenced Controller Services, Parameter Contexts, and Parameter Providers that the corresponding asynchronous update methods enforce. A authenticated user with write access to a Process Group can trigger the flaw by submitting a client-supplied flow definition through these endpoints. As a result, the user can modify or remove components in descendant Process Groups protected by more restrictive access policies and can bind components to Controller Services and Parameter Contexts without authorization for those referenced components; existing verification checks limit the impact to stopped components. Only deployments that use component-level authorization policies are affected, since the framework otherwise enforces write permissions as the security boundary. No public proof-of-concept is known, the flaw is not in CISA's KEV catalog, and no exploitation has been reported.
What to do: Upgrade to Apache NiFi 2.12.0, which applies consistent reference resolution and component authorization across Process Group replacement and versioned flow update methods. Deployments that do not use component-level authorization policies are not affected; those that do should review which users hold write access to Process Groups and audit descendant Process Groups, Controller Service bindings, and Parameter Context assignments for unauthorized changes.
Affected
| Apache NiFi | 1.5.0 through 2.11.0 |
Estimated exposure
largetens of thousands of deployments, of which only the subset using component-level authorization policies is actually exposed — NiFi is widely deployed as an enterprise data-integration platform, suggesting an installation base in the 10k-100k range, but the flaw only applies where component-level authorization policies are configured and requires an authenticated…
Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.
Description
Apache NiFi 1.5.0 through 2.11.0 provide REST API methods that replace the entire contents of a Process Group using a client-supplied flow definition, covering Process Group flow replacement together with versioned flow update and rebase operations. Framework authorization for these methods was limited to read and write privileges on the Process Group itself, unlike the corresponding asynchronous update request methods, which also authorize the components encapsulated in the Process Group along with referenced Controller Services, Parameter Contexts, and Parameter Providers. As a result of the missing authorization, an authenticated user with write access to a Process Group could supply a flow definition that modifies or removes components in descendant Process Groups protected by more restrictive access policies, and could bind components to Controller Services and Parameter Contexts without authorization for those referenced components. Existing verification checks limited the impact to stopped components, and the issue applies only to deployments that use component-level authorization policies, because the framework enforces write permissions as the security boundary. Upgrading to Apache NiFi 2.12.0 is the recommended mitigation, which applies consistent reference resolution and component authorization across Process Group replacement and versioned flow update methods