This indicates an attack attempt to exploit an Authentication Bypass Vulnerability in Cisco Systems Data Center Network Manager.
The vulnerability is due to a hard-coded cryptographic key shared across installations. A remote, unauthenticated could exploit this vulnerability by using the static cryptographic key to craft a valid session token. Successful exploitation of this vulnerability could allow the attacker to bypass authentication and perform arbitrary actions through the REST API with administrative privileges.
Cisco Systems Data Center Network Manager prior to 11.3(1)
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.