This indicates an attack attempt against a Denial of Service vulnerability in MIT Kerberos 5 KDC server.
The vulnerability is due to an error in pre_reprocess_req function when the vulnerability software handles a malformed request. A remote attacker maybe able to exploit this to cause a denial of service condition to the vulnerable server, via a crafted TGS-REQ request.
MIT Kerberos 5 1.10.x to 1.10.4
Denial of Service: Remote attackers can crash vulnerable systems.
Apply patch, available from the vendor's website.