Apache NiFi 1.16.0 through 1.28.0 and 2.0.0-M1 through 2.0.0-M4 include optional debug logging of Parameter Context values during the flow synchronization process. An authorized administrator with access to change logging levels could enable debug logging for framework flow synchronization, causing the application to write Parameter names and values to the application log. Parameter Context values may contain sensitive information depending on application flow configuration. Deployments of Apache NiFi with the default Logback configuration do not log Parameter Context values. Upgrading to Apache NiFi 2.0.0 or 1.28.1 is the recommendation mitigation, eliminating Parameter value logging from the flow synchronization process regardless of the Logback configuration.
Information written to log files can be of a sensitive nature and give valuable guidance to an attacker or expose sensitive user information.
While logging all information may be helpful during development stages, it is important that logging levels be set appropriately before a product ships so that sensitive user data and system information are not accidentally exposed to potential attackers. Different log files may be produced and stored for: