Kibana versions prior to 7.6.3 suffer from a prototype pollution bug within the Upgrade Assistant. By setting a new constructor.prototype.sourceURL value you can execute arbitrary code. Code execution is possible through two different ways. Either by sending data directly to Elastic, or using Kibana to submit the same queries. Either method enters the polluted prototype for Kibana to read. Kibana will either need to be restarted, or collection happens (unknown time) for the payload to execute. Once it does, cleanup must delete the .kibana_1 index for Kibana to restart successfully. Once a callback does occur, cleanup will happen allowing Kibana to be successfully restarted on next attempt.
Kibana versions prior to 7.6.3 suffer from a prototype pollution bug within the Upgrade Assistant. By setting a new constructor.prototype.sourceURL value you can execute arbitrary code. Code execution is possible through two different ways. Either by sending data directly to Elastic, or using Kibana to submit the same queries. Either method enters the polluted prototype for Kibana to read. Kibana will either need to be restarted, or collection happens (unknown time) for the payload to execute. Once it does, cleanup must delete the .kibana_1 index for Kibana to restart successfully. Once a callback does occur, cleanup will happen allowing Kibana to be successfully restarted on next attempt.