This indicates an attack attempt to exploit a Denial of Service vulnerability in CA ARCserve Backup authentication service.
The vulnerability is due to an error when the vulnerable software handles a crafted SunRPC request. A remote attacker may be able to exploit this to cause a denial of service condition on the affected system.
CA ARCserve Backup (For Windows) 12.5
CA ARCserve Backup (For Windows) 15
CA ARCserve Backup (For Windows) 16
Denial of Service: Remote attackers can crash vulnerable systems.
Apply the most recent upgrade or patch from the vendor.