This indicates an attack attempt to exploit an Unauthorized File Upload vulnerability in Tongda Office Anywhere.
The vulnerability is due to insufficient sanitizing of user supplied inputs when handling a crafted request. It allows a remote attacker to upload an arbitrary file onto vulnerable systems via a crafted request.
Tongda OA 2013
Tongda OA 2015
Tongda OA 2016
Tongda OA 2017
Tongda OA V11
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.