This indicates an attack attempt to exploit an Arbitrary File Upload vulnerability in Zohocorp ManageEngine ServiceDesk Plus.
The vulnerability is due to insufficient sanitizing of user supplied inputs in the application when handling a crafted SMTP request. An unauthenticated remote attacker may be able to exploit this to upload an arbitrary file, leading to a possible code execution condition.
Zoho Corporation ManageEngine ServiceDesk Plus 10.0 build 10011 and prior
System Compromise: Remote attackers can execute arbitrary code on vulnerable systems.
Apply the most recent upgrade or patch from the vendor.