This indicates an attack attempt against a Denial-of-Service vulnerability in Open Source Zookeeper that affects IBM BigInsights (IBM Open Platform with Apache Hadoop).
The vulnerability is due to insufficient sanitization of inputs in the application. A remote attacker may be able to exploit this to cause a denial of service condition on the affected system.
IBM BigInsights 4.1, 4.2, 4.2.5
Denial of Service: Remote attackers can crash vulnerable application.
Apply the latest update from the vendor.